Tag Archive for: nutrition

LCHF and kidney function

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Except from MSc (Med) Physiology Dissertation (UCT), by Tamzyn Murphy (RD)

 

Safety concerns have been raised over low carbohydrate high fat (LCHF) diets’ relatively high protein content, for renal function [100]. While protein intake on LCHF diets may be higher than on conventional diets, it seldom exceeds 30 % total daily energy intake (TDEI) [10, 101]. Critics theorise that high protein intake (> 25% of TDEI or > 2 g. kg body weight (BW)-1 [102])  may chronically increase glomerular pressure and hyperfiltration, thereby damaging the kidneys [103] – particularly concerning in Type 2 Diabetes (T2D) with its high nephropathy risk. Indeed protein restriction helps preserve renal function in pre-existing kidney disease [104]. However, evidence doesn’t support the theory that high protein diets impair renal function in the absence of kidney disease [100, 102, 103, 105], even in obese individuals with T2D [106].  In fact, very low carbohydrate high fat (VLCHF) diets may improve renal function [107], as indicated by results showing reversal of diabetic nephropathy in rodents [108] and reduced creatinine concentrations in an intervention study in overweight and obese humans with and without T2D [109].

 

References

  1. Crowe, T., Safety of low‐carbohydrate diets. Obesity reviews, 2005. 6(3): p. 235-245.
  2. Adam‐Perrot, A., P. Clifton, and F. Brouns, Low‐carbohydrate diets: nutritional and physiological aspects. Obesity Reviews, 2006. 7(1): p. 49-58.
  3. Møller, G., et al., Higher Protein Intake Is Not Associated with Decreased Kidney Function in Pre-Diabetic Older Adults Following a One-Year Intervention—A Preview Sub-Study. Nutrients, 2018. 10(1): p. 54.
  4. Martin, W.F., L.E. Armstrong, and N.R. Rodriguez, Dietary protein intake and renal function. Nutrition & metabolism, 2005. 2(1): p. 25.
  5. Rhee, C.M., et al., Low‐protein diet for conservative management of chronic kidney disease: a systematic review and meta‐analysis of controlled trials. Journal of cachexia, sarcopenia and muscle, 2018. 9(2): p. 235-245.
  6. Brinkworth, G.D., et al., Renal function following long-term weight loss in individuals with abdominal obesity on a very-low-carbohydrate diet vs high-carbohydrate diet. Journal of the American Dietetic Association, 2010. 110(4): p. 633-638.
  7. Tay, J., et al., Long-term effects of a very low carbohydrate compared with a high carbohydrate diet on renal function in individuals with type 2 diabetes: a randomized trial. Medicine, 2015. 94(47).
  8. Azar, S., H. Beydoun, and M. Albadri, Benefits of ketogenic diet for management of type two diabetes: a review. J Obes Eat Disord, 2016. 2(2).
  9. Poplawski, M.M., et al., Reversal of diabetic nephropathy by a ketogenic diet. PLoS One, 2011. 6(4): p. e18604.
  10. Hussain, T.A., et al., Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes. Nutrition, 2012. 28(10): p. 1016-1021.

Preparing legumes to maximise nutrition and minimise adverse effects

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By Tamzyn Murphy

BSc Med(Hons) Human Nutrition and Dietetics, RD

 

Legumes (peas, beans, lentils and peanuts) contain pesky and destructive anti-nutrients, which bind to other nutrients in food, inhibiting their absorption. Anti-nutrients also irritate the gut-lining, causing stomach trouble and making the gut ‘leaky’ – allowing proteins and other-usually ‘banned’ components through the gut wall and into the bloodstream. This may result in immune system problems including inflammation and possibly even autoimmune diseases.

 

However, legumes (especially soya) are great proteins sources for vegetarians, and even more so for vegans. They’re also a good source of fibre, B vitamins and other micronutrients. In order to reap legumes’ nutritional rewards without incurring the destructive health effects wreaked by their anti-nutrients you have to prepare them right.

A. Soak, sprout, cook, grind and ferment: The best way to do away with pesky anti-nutrients.

  1. Soak:
    • Cover dry legumes with warm water, acidified with vinegar or lemon juice, in a glass jar.
    • Cover the jar’s opening with a clean cloth secured with a rubber band.
    • Place the jar in a warm location for 12-24 hours.
    • Drain water out through the cloth and then rinse the legumes and drain again.
  1. Sprout
    • Store the damp legumes in a dark place (e.g. cupboard). Ensure the jar is on its side. Elevate the base slightly using a rolled-up or folded dish cloth. Place paper towels or a dishcloth beneath the cloth-covered side of the jar to allow the remaining water to drain out.
    • Rinse and drain the legumes twice a day.
    • Allow them to sprout (germinate) for a total of 3-5 days.
  1. Cook (boil) (optional/preferable)
    • Place legumes in pot.
    • Cover with water.
    • Bring to the boil on high heat.
    • Once boiling, turn heat down to low and allow to simmer for at least one hour. Ideally you can leave them to cook all day in a slow cooker.
  1. Grind, mash or break (optional/preferable)
    • Use a blender or food processor or mash (if cooked)
  2. Ferment
    • Add a powdered starter culture (as directed) or kefir (about one tablespoon culture per one cup of legumes) to the damp legumes in the jar. Seal the jar with a tight-fitting lid this time.
    • Allow the legumes to ferment for several days.
    • The jar needs to be ‘burped’ (briefly opened to release gases) daily. A protruding lid indicates that too much gas is building up, which needs releasing.

 

B. Soak properly and cook thoroughly: An abbreviated version that’s not as effective as the process above, but still inactivates most of the anti-nutrients.

  1. Soak:
    1. Soak dry legumes in warm water, acidified with vinegar or lemon juice, for 12 hours (preferably in a warm location)
  2. Drain legumes (discard water)
  3. Rinse legumes
  4. Repeat steps a, b and c twice (totalling 36 hours of soaking time)
  5. Boil legumes: Follow A.3. above
  6. Ferment (optional)
  7. Follow A.5. above. However, before fermenting it is essential to ensure that you break the skins by mashing or exerting enough downward pressure on the legumes to just break them.

 

References:

  1. Food & Wine. Step-by-step guide to Sprouting beans at home. http://www.foodandwine.com/slideshows/sprouting-beans#!slide=4
  2. Cultures for health. Fermenting beans and legumes. http://www.culturesforhealth.com/fermenting-beans-legumes
  3. Guyenet S. Traditional preparation methods improve grains’ nutritive value. 4 May 2010 http://wholehealthsource.blogspot.com/2010/05/traditional-preparation-methods-improve.html
  4. Nagel R. Living with phytic acid. The Weston A Price Foundation. 26 Mar 2010. http://www.westonaprice.org/health-topics/living-with-phytic-acid/

Can kids ‘Bant’?

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By Tamzyn Murphy

BSc Med(Hons) Human Nutrition and Dietetics, RD

 

We await the verdict of Prof Tim Noakes’ HPCSA trial over a tweet in which he “advised” a mother to wean her child onto LCHF food. In the meantime let’s take a closer look at the evidence regarding Banting and kids…

 

Today’s children are the first generation expected to live shorter lives than their parents [1]. We are seeing more overweight children and adolescents than ever before [2, 3]. And we know that overweight children are likely to grow up into overweight adults, with associated health risks (e.g. heart disease and diabetes) [4]. It is clear that the way most children are eating is not doing their health any favours.

 

If we always do what we’ve always done, we’ll always get what we’ve always got

 

Sickly sweet South African kids

Eating too much sugar is associated with dental caries and increased obesity risk [3]. Both of which are prevalent health concerns amongst South African children.

 

We know that children and adolescents in South Africa, and across the globe, eat more sugar than adults. In fact one study reported that South African children eat about 50g (12.5 teaspoons) of sugar each day, while South African adolescents consume as much as 100g (25 teaspoons) per day [3]. This represents 10-20% of daily calorie consumption [3]. South African adults on the other hand, are thought to be eating approximately 38-51g (9-13 teaspoons) of sugar each day, contributing 10-15% of their calories [3].  The World Health Organisation’s guidelines recommend a maximum of 5% of daily calories from sugar – that’s no more than 7 teaspoons daily from all sources. Reducing or even eliminating our children’s added sugar consumption can only be good for their health.

 

Most medical practitioners and scientists will agree that drastically reducing or even cutting out children’s sources of added sugar can only be good for them. But the question remains, can children safely following a low carbohydrate, high fat (LCHF) diet (popularly known as Banting in South Africa), that’s devoid of starches and wholegrains as well as sugar?

 

Evidence: very LCHF diets in children

Although, very little research has been done on LCHF eating in children, a few studies have shown that overweight  kids and teens (6-18 years of age) who followed a LCHF, containing less than 60g of carbs each day, successfully lost weight, without negatively affecting the levels of fat and cholesterol in their blood [5, 6]. The authors suggest that reducing dietary carbohydrate may be a possible treatment for insulin resistance in children and adolescents.

 

Of note, a very low carbohydrate, ketogenic diet has been successfully used to treat childhood epilepsy for almost a century [7]. A modified version of the Atkin’s diet, also very low in carbohydrates (it only contains 10g), but easier to follow than the ketogenic diet (as, unlike the ketogenic diet it doesn’t also limit calories and protein), has been used successfully for the same purpose for over a decade. Unlike protein and certain fats, dietary carbohydrates are not essential nutrients – our bodies can make them from scratch to use as fuel. So it’s not surprising that both the ketogenic and modified Atkin’s (probably more so than the ketogenic diet, which also limits protein and calories) diets are considered safe when used in conjunction with multivitamin and calcium supplementation [8, 9].

 

“Banting” for children needn’t be very low carb

It’s important to bear in mind that most children who follow a LCHF don’t need to drastically restrict carbohydrates to the ketogenic levels (<60g per day) investigated in the studies discussed above (A LCHF diet typically provides 20-120g of carbohydrate daily or 5-30% of total energy intake). So, while added sugar, starches and grains will be eliminated from their diets, other wholefood sources of carbohydrates won’t be excluded (e.g. dairy, starchy vegetables, nuts, seeds, fruit and even properly prepared legumes).  I recommend that children only restrict their carbohydrates to below 60g under the supervision of a dietitian or knowledgeable medical doctor.

 

Provided that a child consumes the recommended 3 portions of dairy daily and eats enough vegetables, supplementation shouldn’t be any more necessary on this diet than with any other. While I don’t suggest being too restrictive about children’s starchy vegetable, fruit and nut consumption, excluding starches (in the form of grains) and added sugar from children’s diets shouldn’t pose any health risk and will likely come with a host of benefits. Especially considering that these restrictions are done in the context of a diet that emphasises avoiding processed food, while eating REAL, nutrient dense foods.

 

“Banting” for kids simplified

  • Eat real food. Avoid processed food.
  • Eat freely: Avocados, olives, other vegetables, dairy, fish, poultry, meat (including organ meats), eggs, butter, olive oil, coconut oil
  • Eat moderate amounts: Fruit, nuts, seeds, properly prepared legumes (beans, peas, lentils)
  • Exclude: Added sugar (in all its forms), processed food, grains (although it’s likely fine to include limited amounts of the less irritating grains such as oats or quinoa)

 

References 

[1] Olshsky SJ, Passaro DJ, Hershow RC, et al. A Potential Decline in Life Expectancy in the United States in the 21st Century. N Engl J Med 2005; 352:1138-1145 

[2] Gupta N, Goel K, Shah P, Misra A. Childhood Obesity in Developing Countries: Epidemiology, Determinants, and Prevention. Endocrine Reviews. Jan 2012;33(1) 

[3] Steyn N, Temple NJ et al. Evidence to support a food-based dietary guideline on sugar consumption in South Africa. BMC Public Health. 2012;12:502

[4] Singh AS, Mulder C, Twisk JWR, et al. Tracking of childhood overweight into adulthood: a systematic review of the literature. Obesity Reviews. Sep 2008;9(5):474-88 

[5] Gow ML, Ho M, Burrows TL, et al. Impact of dietary macronutrient distribution on BMI and cardiometabolic outcomes in overweight and obesechildren and adolescents: a systematic review. Nutr Rev. 2014 Jul;72(7):453-70. 

[6] Sondike SB, Copperman N, Jacobson MS. Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factor in overweight adolescents. J Pediatr. 2003 Mar;142(3):253-8. 

[7] NICUS. The Ketogenic Diet…Fa(c)t or fiction? 2007

[8] Tonekaboni SH, Mostaghimi P, Mirmiran P, et al. Efficacy of the Atkins diet as therapy for intractable epilepsy in children. Arch Iran Med. 2010 Nov;13(6):492-7. 

[9] Suo C, Liao J, Lu X, et al. Efficacy and safety of the ketogenic diet in Chinese children. Seizure. 2013 Apr;22(3):174-8. 

Best first food for baby: Meat vs cereal

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By Tamzyn Murphy

BSc Med(Hons) Human Nutrition and Dietetics, RD

 

South African personality, sports scientist and Emeritus UCT Professor Tim Noakes is making news headlines again as the second and last day of the closing arguments of his “Baby Banting” trial before the Health Professions Council of South Africa (HPCSA) commences. The council is investigating Noakes for giving unconventional and un professional advice. The complaint laid by Association for Dietetics (ADSA) president, Claire Julsing-Strydom, is over ‘advice’ that Noakes tweeted in response to a mother’s query regarding the best food to introduce to her baby. Noakes advised the mother to introduce low carbohydrate, high fat (LCHF), Banting-friendly foods (which include meat and vegetables) to her baby from 6-month of age.

While the HPCSA will determine whether babies should or shouldn’t Bant, it is clear that Noakes is right about at least one thing: meat is far superior to cereal as babies’ first food. Health authorities’ recommendations that meat, meat alternatives (like eggs) and iron-fortified cereal are the best first food for babies imply that these are options are nutritional equals [1]. They are not. Here’s why meat beats cereal hands down.

 

Meating babies’ nutritional needs

Iron deficiency is very common in children in South Africa [2,3], and across the globe [4]. Many infants also don’t eat enough iron [2]. Infants with iron deficiency have impaired growth, mental development and problem solving ability [4]. Iron deficient babies score worse for mental and motor functioning when they’re older too [4]. By 6 months of age babies run out of iron stores [4]. Meat, fish and poultry are rich sources of the most readily absorbed heme form of iron. The iron contained in iron fortified cereal on the other hand, is in a non-haem form that is very poorly absorbed [4].

Meat, liver, poultry and fish – given as babies’ first foods in many traditional societies [1] – were the obvious iron-rich first foods to be introduced to babies before iron-fortified cereals were available. Since iron-fortified cereal was introduced it has replaced meat as the first food of choice for babies [4]. Not only is it a poor replacement as a source of bioavailable iron, but it also contains anti-nutrient phytates, which interfere with iron absorption, thereby reducing its bioavailability even further [2]. Therefore, cereal, even if it’s fortified with iron, may not be able to provide the iron that 6 month olds so desperately need.

Interestingly, zinc deficiency is also very common in babies and children. Meat is an excellent source of zinc. Introduction of meat as opposed to cereal as an early complementary food for exclusively breastfed infants is associated with improved zinc, iron and protein intake.  Babies fed meat instead of cereal have a higher head circumference and possibly also improved psychomotor development [5].

 

A weighty issue

Dietitian text books recommend that sugar and salt are not added to babies foods. Yet in the same breath they say that fortified infant cereal – usually packed with added sugar – is the first food to be introduced to babies [4].

Dietary sugar is linked to dental caries and the development of obesity and other lifestyle-related diseases. Even if parents do find baby cereal options that don’t include added sugar, they are still very refined (processed) and incredibly high in fast-release (high GI) carbohydrates.

Introducing cereals and fruit as babies’ first solid food is linked to the development obesity later in life [6]. Meat contains no carbohydrate and is high in fat and protein. A high fat intake during babies’ complementary feeding period doesn’t appear to increase their risk of becoming obese later [7]. There has been concern that high protein intake during infancy promotes weight and fat gain. However, a recent study indicates that this only holds true for high levels of protein from cow’s milk in formula fed infants. Breastfed babies who were fed meat instead of cereal, gained more weight and grew taller than those fed cereal, but they didn’t get fatter [8]. This indicates that higher protein levels from meat may not be linked to fatness after all.

Parents and health professionals await the outcome of Noakes’ HPCSA trial with bated breath. For now though, at least one aspect is clear: introducing ‘Banting-friendly’ meat to babies is a far better option than introducing cereal. From 6 months of age, babies should be offered pureed meat, liver, poultry, fish and eggs, progressing to the introduction of a variety of foods from family meals, such as vegetables mixed with pasture-fed butter, olive oil or breastmilk. Breastmilk continues to be the main source of nutrition throughout the first year. Breastfeeding is recommended for at least one year whenever possible, and preferably for up to two years or beyond.

 

References

[1] Health Canada. Nutrition for health term infants: Recommendations from six to 24 months. 24 Mar 2014

[2] Faber M, Wenhold F. Nutrition in contemporary South Africa. AJOL. 2007;33(3):393-400

[3] Visser J, Herselman M. Anaemia in South Africa: the past, the present and the future. S Afr J Clin Nutr. 2013;26(4):166-167

[4] Mahan LK, Escott-Stump S. Krause’s Food & Nutrition Therapy. International Edition 12. Saunders Elsevier. 2008

[5] Krebs NF, JE Wescott, N Butler, et al. Meat as a First Complementary Food for Breastfed Infants: Feasibility and Impact on Zinc Intake and Status. J Pediatr Gastroenterol Nutr. Feb 2006;42(2)

[6] Caroli M, Mele RM, Tomaselli MA, et al. Complementary feeding patterns in Europe with a special focus on Italy. Nutr Metab Cardiovasc Dis. Oct 2012;22(10):813-8

[7] Michaelsen KF, Larnkjaer A, Molgaard C. Early diet, insulin-like growth factor-1, growth and later obesity. World Rev Nutr Diet. 2013;106:113-8

[8] Tang M, Krebs NF. High protein intake from meat as complementary food increases growth but not adiposity in breastfed infants: a randomized trial. Am J Clin Nutr. Oct 2014;ajcn.088807

Diets that do and diets that don’t: Part 4 – The Dukan Diet

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By Tamzyn Murphy

BSc Med(Hons) Human Nutrition and Dietetics, RD

 

Unlike the typical low carb diet, Dukan is high in protein (starting at 40% of calories) and low in fat (20% of calories). It’s big on rules and the restrictive phases are incredibly strict – any indiscretion is seen as a major failure. The idea is to replace much of your dietary carbs and fat with protein, which is filling, low in calories and takes time and work to digest. Studies on low carb, low fat, high protein diets show that you’ll naturally eat far fewer calories, feel full and you’ll likely experience metabolic benefits, including improved cholesterol, blood fat, glucose and insulin levels, thereby possibly reducing heart disease, diabetes and metabolic syndrome risk.[i], [ii] But weight loss benefits don’t appear to out-do other diets.

There are four phases. Phase one lasts about 5 days and consists almost exclusively of protein food – meat, seafood, poultry, eggs, vegetable-protein and fat-free dairy. No vegetables. Phase two allows non-starchy veg to be added to phase one’s protein foods, on every alternate day, and continues until you’ve lost the weight. The third phase last a few months and allows all the protein food and non-starchy veg you like, as well as limited fruit, whole grain bread and cheese. Phase three also allows two starch servings (e.g. pasta) and two anything-you-want meals each week. Phase four: eat what you like six days of the week, bearing in mind what you learnt during phase 3. On day seven you must eat like you did in phase one. A daily oat bran serving forms part of each phase, probably in an attempt to increase the fibre content of the diet.

Dukan’s excessive protein may increase your risk of gout[iii] and put strain on the kidneys[iv]. And a high protein and low fibre diet is bound to give you constipation. Cutting out entire food groups may put you at risk for nutritional deficiencies. So if you’re insistent on following this diet, it’s probably prudent to take a complete vitamin and mineral supplement, especially during the first two very restrictive phases. Phase four’s sudden dietary freedom may leave you directionless and reverting back to your old ways, resulting in rebound weight gain. And with all the expensive protein you’re guzzling, prepare for dent in your bank balance; as well as a conscience-prick at the number of animals that are being killed and the environmental impact of a carnivorous diet.

References

[i] Dumesnil JG, Turgeon J, et al. Effect of a low-glycaemic index–low-fat–high protein diet on the atherogenic metabolic risk profile of abdominally obese men. British Journal of Nutrition. Nov 2001;86(5):557-68 

[ii] Farnsworth E, Luscombe ND, et al. Effect of a high-protein, energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women.

[iii] Torralba KD, De Jesus E, Rachabattula S. The interplay between diet, urate transporters and the risk for gout and hyperuricemia: current and future directions. Int J Rheum Dis. 2012 Dec;15(6):499-506 

[iv] Juraschek SP, Appel LJ, et al. Effect of a high-protein diet on kidney function in healthy adults: results from the OmniHeart trial. Am J Kidney Dis. 2013 Apr;61(4):547-54

Diets that do and diets that don’t: Part 3 – The Blood Group Diet

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By Tamzyn Murphy

BSc Med(Hons) Human Nutrition and Dietetics, RD

 

Eat right for your type, by naturopathic doctor Peter D’Adamo, was first published almost 20 years ago, but it’s more popular than ever. It advises people to eat certain foods and avoid others based on their blood type – O, A, B or AB. According to D’Adamo, your blood type determines how your body digests lectins (anti-nutrient proteins found in certain foods). Apparently, eating lectins that are incompatible with your blood type causes a host of adverse health effects, from bloating and inflammation to weight gain. Allegedly, your blood type even determines what exercise suits you best.

 

Foods are categorised as ‘highly beneficial’ (with medicinal effects), ‘neutral’ (acting as a food) or ‘avoid’ (toxic) for each blood type. O (“for old” – humanity’s oldest blood line) types are told to follow a meat-based diet and vigorous exercise programme.  Type A (for “agrarian”) should eat vegetarian food and exercise gently. B types are thought to have nomadic genes and digestive systems that can tolerate many foods, except, amongst other things, wheat, corn and lentils. Bs should exercise moderately. D’Adamo says the “modern” AB blood type has a sensitive digestive tract and should avoid meat and poultry but can enjoy seafood, tofu, dairy, and most fresh produce. ABs should do calming exercises.

 

People probably love this diet because it sounds scientific; but nothing could be further from the truth. There is absolutely no evidence that some foods or exercises are good for people of one blood type and “dangerous” for another. It appears that D’Adamo has randomly bestowed fictional characteristics upon people of different blood types and thumb-sucked foods to put on his ‘beneficial’ and ‘avoid’ lists. If the diet has worked for you it’s probably because all blood types are encouraged to eat real, whole and natural foods in place of processed, sugary and fatty choices, and exercise is always recommended. These are prudent health recommendations that’ll work for anybody. Also each of the four diets loosely resembles a diet that has been shown to have weight loss benefits: The O diet’s a variation on the typical high protein, low carb diet; A’s vegetarian; B’s somewhat similar to the Mediterranean and low GI/GL diets and AB is Pescatarian. In my opinion, the blood type diet’s a perfect example of a fad diet that profits from people’s desperation. If it works, it’s not for the reasons you think.

 

References

[i] WebMD. The eat right for your blood type diet. Sep 2013

[ii] Eat right for your type. www.dadamo.com. Sep 2013

Diets that do and diets that don’t: Part 2 – The Paleo Diet

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By Tamzyn Murphy

BSc Med(Hons) Human Nutrition and Dietetics, RD

 

The Paleo diet, founded by researcher Loren Cordain (PhD), is based on what our caveman ancestors ate. It includes only the foods we’ve eaten for most of human history; which we’ve evolved to eat. Like Atkins, Paleo is a low carb, moderate protein, high fat diet. You’re allowed as much meat, fish, poultry, eggs, natural fat (e.g. butter, olive oil, avocado) and non-starchy vegetables as you like. Unlike Atkins, Paleo allows any other foods that our caveman ancestors ate, like any root vegetables, nuts, seeds and fruit.  We only became dependent on farmed foods, like grains, legumes (beans, peas, lentils) and dairy, relatively recently – less than 500 generations ago – with the advent of agriculture. So our genes haven’t had much time to adapt to problem compounds in these foods, theoretically causing inflammation and weight gain.

Indeed, grains and legumes contain anti-nutrients (like lectin and gluten) which interfere with nutrient absorption, irritate intestinal lining (promoting leaky gut) and yield other toxic effects. Cereal grains, particularly wheat, are the worst.[i] So there’s a case to be made for limiting or even eliminating them. But legumes’ anti-nutrients are largely inactivated by cooking at high temperatures, which makes them relatively safe[ii]. Plus legumes contain numerous beneficial compounds.[iii] They’re also are an important protein source – particularly important for vegetarians, vegans and the poor; not to mention ethical and environment-friendly meat-replacements. There’s no evidence that legumes increase weight gain. Research shows that dairy doesn’t have inflammatory[iv] or weight promoting effects[v]. In fact it may do the opposite.

So, the theory behind Paleo is sound – eat whole, unprocessed food as much as possible. But including moderate amounts of dairy and legumes may offer more benefits than risks. Paleo loses points on the expense-front, and due to the lack of dairy you might want to supplement with calcium and vitamin D, unless you’re getting plenty of other calcium rich foods and enough sunshine.

 

References

[i] Cordain L. Cereal Grains: Humanity’s Double Edged Sword. Simopoulos AP (ed): Evolutionary Aspects of Nutrition and Health.Diet, Exercise, Genetics and Chronic Disease. World Rev Nutr Diet. Basel, Karger, 1999;84:19-73

[ii] Pusztai A, Grant G. Assessment of lectin inactivation by heat and digestion. Methods Mol Med. 1998;9:505-14 

[iii] Bouchenak M, Lamri-Senhadji M. Nutritional quality of legumes, and their role in cardiometabolic risk prevention: a review. J Med Food. 2013 Mar;16(3):185-98 

[iv] Labonté MÈ, Couture P, et al. Impact of dairy products on biomarkers of inflammation: a systematic review of randomized controlled nutritional intervention studies in overweight and obese adults. Am J Clin Nutr. 2013 Apr;97(4):706-17 

[v] Abargouei AS, Janghorbani M,  et al. Effect of dairy consumption on weight and body composition in adults: a systematic review and meta-analysis of randomized controlled clinical trials. Int J Obes (Lond). 2012 Dec;36(12):1485-93 

A lower carbohydrate higher fat diet and children’s development and concentration

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Real Food Dietitian, Bridget Surtees, talks to Real Meal Radio about whether a lower carbohydrate higher fat diet affects children’s development and concentration.

The first Prof Tim Noakes ‘Banting’ lecture that I ever attended

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“At any given moment there is an orthodoxy, a body of ideas which it is assumed that all right-thinking people will accept without question… A genuinely unfashionable opinion is almost never given a fair hearing, either in the popular press or in the highbrow periodicals.” – George Orwell, Animal Farm, 1945

 

By Tamzyn Murphy Campbell

BSc, BSc Med(Hons) Human Nutrition and Dietetics, RD

 

It’s January 2013. Waiting for his talk to start, in his grey suit and Nike trainers, Professor Tim Noakes looks far trimmer than when I saw him last, five years ago at a talk on University of Cape Town’s medical campus. His weight loss should come as no surprise though, considering he’s been following his own advice, avoiding carbohydrates, which he claims is the key to solving our global obesity epidemic.

“I’ve been declared officially mad by my faculty,” begins Prof Noakes. Despite being shunned by his peers for his unconventional dietary advice, Prof Noakes appears happy and relaxed and impossible not to like with a big friendly smile stretched across his face. Maybe it’s insanity that’s got him so at ease in the face of scorn. Or perhaps he’s just calmly confident that he’s right. As he explains later in the talk, he has acted ethically by correcting the misconceptions responsible for our ill health as soon as he became aware of them.

Let me walk you through Prof Noake’s argument and then you decide on which side of the nutritional fence you’d like to sit.

 

WHY THE CONTROVERSY?

It’s accepted as fact that we get fat because we eat too much and exercise too little: the twin sins of gluttony and sloth. The prevailing belief is that a high fat intake promotes weight gain and heart disease. Authorities say that saturated fat (mainly from animal-derived food sources) raises cholesterol, which in turn clogs our arteries leading to heart disease. This knowledge stems from the Seven Country Study, published in 1963 and conducted by a scientist called Ancel Keys who found that men in countries with diets high in saturated fat suffered from more heart disease. What Keys failed to mention was that countries that didn’t support this finding were left out of his study. He also failed to report that heart disease incidence happened to increase with a higher sugar intake.

Flying in the face of what we accept as the fundamental truths of nutrition, Prof Noakes declares that fat doesn’t raise cholesterol and cause heart disease nor promote weight gain and we certainly aren’t getting fat because we’re eating too much and exercising too little. He doesn’t expect us to blindly believe him though, presenting us with statistics and cutting-edge scientific intervention and review studies that back up what he has to say. This unconventional opinion, especially from such a well-published and respected scientist, has thrown the South African scientific and medical community into a furor. But according to Prof Noakes, the most outraged are those scientists who are receiving funding from the food industry.

 

MONEY, POLITICS & CORRUPTION

“It is difficult to get a man to understand something, when his salary depends on his not understanding it,” quotes Prof Noakes when a member of the audience asks how we can possibly believe him when so many scientists disagree. The food industry’s lifeblood is tasty and addictive food and beverages, packed full of carbohydrates and sugar. According to Prof Noakes, if South Africa’s university departments who rely on industry funding – such as cardiology, pharmacology or nutrition – were to speak out against carbohydrates and sugar (or the efficacy of prescription medication in the case of pharmacology faculties) then their research funding would be pulled and their departments may as well shut down.

Prof Noakes says that a researcher who acts as industry’s mouthpiece stands to gain a lot of money and exposure: “These companies will support any researcher that will stand up here and punt exercise to lose weight [in order to avoid recommendations that’ll reduce their sales]”. He goes on to say that industry-funded study results are biased, misleading and often downright wrong. “Ninety-five percent of nutrition advice is based on association studies,” Prof Noakes explains, “and 85% of association studies are wrong.” Association studies show how factors change in relation to each other but are unable to show that one factor causes the other. For example, in Ancel Keys’ Seven Country Study heart disease increased in countries that had higher saturated fat consumption. This doesn’t mean that saturated fat caused the increased heart disease. Other factors could be to blame. As it turns out, sugar consumption happened to increase along with saturated fat in these countries and could possibly explain the increased heart disease risk.

According to Prof Noakes, the two biggest funders of US nutrition research, the National Institute of Health and the US government, will only fund studies that show that high carbohydrate intake is healthy.  This is following a decision made by the US senate, in 1977, to fund corn, soya and vegetable oil agriculture, and the development of US dietary guidelines in the same year recommending that Americans get 50–60% of their total daily energy from carbohydrates, while limiting dietary fat and cholesterol. Prof Noakes explains that these decisions were made to be in line with what grain farmers and the major industry-controlling food companies wanted.

 

CARBS MAKE US FAT

Prof Noakes explains that we’ve genetically evolved to eat a low carbohydrate diet, saying that we don’t actually need to eat carbohydrate to survive, whereas protein and fat are essential for survival. Also, it appears that our calorie and carbohydrate consumption has increased concurrently with obesity over the decades, but our fat intake has remained relatively constant. This implies that it’s not the fat that’s to blame for our ballooning waistlines.

So if Prof Noakes is right and carbohydrates really are to blame, then how do they do it? Prof Noakes claims that carbohydrates upset the body’s natural energy-regulation ability – your homeostat that’s supposed to balance your calories consumed with the calories you burn (calories in versus calories out).  Eating more carbs these days means we’re getting lots of glucose into our bloodstreams. Our bodies have to secrete more of the hormone insulin to keep these potentially damaging glucose levels under control. And as it turns out, insulin promotes fat storage and makes us eat more.

Prof Noakes says that insulin promotes liver triglyceride (fat) production and storage, leading to metabolic problems including diabetes and obesity.[1] Insulin also encourages fat storage in adipose tissue (fat stores), particularly in those who’re genetically predisposed, thereby promoting weight gain. According to Prof Noakes, those who are naturally carbohydrate resistant consistently oversecrete insulin in response to eating carbs. This consistently high insulin means that dietary carbs are continuously being converted to fat and stored away for a rainy day.

All of this carbohydrate conversion and fat storage leaves little energy available to your cells, so you quickly get hungry again, craving a quick-release energy source like, you guessed it, carbohydrates. And so the vicious cycle begins. Prof Noakes says that since he’s been on his low-carb diet he only gets hungry every 16–24 hours. To make matters worse it turns out that carbs are addictive. They temporarily boost the pleasure chemicals in your brain and your mood. Then they drop again, leaving you craving your next carbohydrate fix. “Addictive food choices cause obesity in those with insulin resistance,” says Prof Noakes, “it took me 14 months to stop adding sugar to my tea and coffee but it’ll take me one day to go back.”

 

SOME AND NOT OTHERS

Why then do only some of us get fat on a high-carbohydrate diet, while others can eat what they like and stay lean? Prof Noakes explains that if you’re genetically prone to carbohydrate or insulin resistance, as most of us are, then your body goes into fat production and storage mode in response to carbohydrates and insulin, resulting in constant hunger, inactivity and, consequently, weight gain. If you’re one of the lucky few who can eat what you like and stay lean then your body is better able to utilise carbohydrates as a fuel source rather than storing it as fat in response to insulin. Prof Noakes says that the amount of dietary carbohydrates different people can tolerate varies. “The difference between being lean, as I am, or fat is 25g of carbohydrates,” claims Prof Noakes. This amount is very low. Most people will be able to lose excess fat and maintain a stable healthy weight at somewhere between 20 and 120g of carbohydrates daily.

Prof Noakes also implicates carbohydrates in the dreaded middle-age spread: “As we get older we get more carbohydrate resistant”. So if you could eat what you liked in your youth but are now finding that a spare tire has settled around your middle, cutting all starches and sugars may help you maintain a svelte shape.

 

CARBS MAKE US SICK

“Eighty percent of diseases are caused by nutrition.” According to Prof Noakes, carbohydrates aren’t just to blame for the obesity epidemic but also for the chronic diseases that plague modern society. “There’s one cause [carbohydrates], one treatment [cutting carbohydrates] for all conditions,” reveals Prof Noakes – listing diabetes, cardiovascular disease, metabolic syndrome, high blood pressure, gout, cancer and even Alzheimer’s. Prof Noakes calls insulin the aging hormone, saying, “Alzheimer’s is caused by high insulin” and “cancer, specifically colon and breast cancer, is driven by high insulin”.

Prof Noakes addresses critics’ main arrow in the quiver against a low-carb diet, being that its high fat content increases heart disease risk. It turns out that well-designed, up-to-date research indicates that saturated fat appears to have no effect on death rates[2] and heart disease.[3] A higher carbohydrate intake, on the other hand, increases all the heart disease risk factors.[4] It boosts levels of fats, bad cholesterol (small LDL), insulin and glucose in the blood, while reducing the good cholesterol and boosting your belly.

“If you are eating these [starches] then that’s what you will die from,” Prof Noakes acknowledges with a sad smile.

 

TIPS

If you struggle with your weight, get hungry every three hours or so and dread exercise then Prof Noakes explains that you’re probably carbohydrate resistant and can benefit from cutting down on dietary carbohydrates. His advice? “If it doesn’t occur in nature, don’t eat it.”

A low-carbohydrate diet is typically high in fat and moderate in protein. You’ll need to cut out all grains, sugar and trans fats. Stick to meat, poultry, fish, eggs, vegetables (like spinach, broccoli, tomatoes, mushrooms, lettuce, cucumber, carrots), nuts, avocado pear and olive oil. Prof Noakes warns to stay away from most other vegetable oils though, specifically those high in pro-inflammatory and blood-clotting omega-6 fats like sunflower and corn oils. Full-cream or low-fat dairy products are acceptable in moderation. Depending on how much carbohydrate you can tolerate before you start to balloon, you may even be able to squeeze in a few legumes, a touch of starchy vegetables and low-sugar fruit (like berries and apples) – though it’s probably best to tread with caution when trying these food items on your low-carb diet. Prof Noakes cautions to watch out for sweet beverages, advising sticking to unsweetened water, tea and coffee. And he suggests that most people could benefit from supplementation with omega 3 fats and vitamin D (particularly if you have mid to low range vitamin D levels like he has), due to the strong scientific evidence supporting their use.

 

References include

[1] Petersen KF, Dufour S, et al. The role of skeletal muscle resistance in the pathogenesis of metabolic syndrome. PNAS. Jul 2007;104(31):12587-94 http://www.pnas.org/content/104/31/12587.full.pdf+html

[2] Schoenaker DA, Toeller M, et al. Dietary saturated fat and fibre and risk of cardiovascular disease and all-cause mortality among type 1 diabetic patients: the EURODIAB Prospective Complications Study. Diabetologia. 2012 Aug;55(8):2132-41 http://www.ncbi.nlm.nih.gov/pubmed/22526612

[3] Howard BV, Van Horn L, et al. Low-fat dietary pattern and risk of cardiovascular disease: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial. JAMA. Feb 2006;295(6):655-66. http://www.ncbi.nlm.nih.gov/pubmed/16467234

[4] Siri-Tarino et al. Saturated fat, carbohydrate and cardiovascular disease. Am J Clin Nutr. Mar 2010;91(3):502-9 http://ajcn.nutrition.org/content/91/3/502.full.pdf+html