[MeganParticipant]

Sugar, specifically fructose, has received a lot of attention lately after the viral video lecture and articles by Robert Lustig in 2006. Many researchers have tried to evaluate the role of fructose and its possibly toxicity in the human body. Some researchers are claiming like Lustig that increased fructose consumption mainly from sugar and high fructose corn syrup in the American diet, is the cause for the obesity epidemic and rise in metabolic syndrome. Fructose is thought to potently stimulate lipogenesis (1). The conversion of fructose to the glucose takes place almost exclusively in the liver and therefore is believed to cause non-alcoholic fatty liver disease (NAFLD) when done in high amounts (1) (thus Lustig comparison of fructose to alcohol). In a study by Ouyang et al. Participants with NAFLD were compared to controls matched for gender, age, and BMI. Those with NAFLD consumed 2-3 times more fructose than their control counterparts, which indicated that excessive fructose consumption, may play a role in the mechanism underlying the development of NAFLD (2).
There is a large body of evidence to show the possibility that a high fructose diet leads to obesity, diabetes, and dyslipidemia in rodents (3). In humans, these same effects are seen with high calorie diets, but not fructose exclusively (3). High fructose consumptions has been shown to increase plasma triglycerides in some studies, however further effects of this are unknown (3). Another study looked at daily fructose consumption of over 17,000 American subjects age 19-80 years and found that fructose was rarely consumed alone, only contributed to about 37% of total sugar intake and 9% of energy intake. They also found that it was not positively associated with serum triglycerides, HDL, cholesterol, glycohemoglobin, uric acid, blood pressure, waist circumference or BMI. (4)
In a recent Questions and Answer article with BMC, renowned sugar expert Luc Tappy stated that, “Given the substantial consumption of fructose in our diet, mainly from sweetened beverages, sweet snacks, and cereal products with added sugar, and the fact that fructose is an entirely dispensable nutrient, it appears sound to limit consumption of sugar as part of any weight loss program and in individuals at high risk of developing metabolic diseases. There is no evidence, however, that fructose is the sole, or even the main factor in the development of these diseases, nor that it is deleterious to everybody, and public health initiatives should therefore broadly focus on the promotion of healthy lifestyles generally, with restriction of both sugar and saturated fat intakes, and consumption of whole grains, fresh fruits and vegetables rather than focusing exclusively on reduction of sugar intake” (5).

1: Varman ST. Fructose induced lipogenesis: from sugar to fat to insulin resistance. Trends in Endocrinology & Metabolism. 2011; 22(2): 60-65.

2: Ouyang X, Cirillo P, Sautin Y, et al. Fructose consumption as a risk factor for non-alcoholic fatty liver disease. Journal of Hepatology. 2008; 48(6): 993-999.

3: Tappy L, Lê KA, Tran C, Paquot N. Fructose and metabolic disease: New findings, new questions. Nutrition. 2010; 26(11): 1044-1049.

4: Sun SZ, Anderson GH, Fickinger BD, Williamson-Hughes PS, Empie MW. Fructose and non-fructose sugar intakes in the US population and their associations with indicators of the metabolic syndrome. Food Chem Toxicol. 2011; 49(11); 2875-2882.

5: Tappy L. Q&A: “Toxic” effects of sugar: should we be afraid of fructose? BMC Biology. 2012; 10(42) Available at: http://www.biomedcentral.com/1741-7007/10/42.

[MeganParticipant]

The popular paleo diet has the basic rule, “if cavemen didn’t eat it, neither should you”. So the diet consists of non-processed foods that could be hunted, fished, or gathered, such as meat, fish, poultry, eggs, vegetables, fruits, roots, and nuts. In this diet there is no dairy, refined grains, legumes (beans and peas), sugar, or salt. This way of eating is thought to prevent diseases of modern age, but may also lead to nutrient deficiencies, such as B vitamins from grains or vitamin D and calcium from dairy.
One limitation of this diet is the differences in out food supply and our ancestors. Modern meat contains about 20-30% fat while wild African game contained about 4% and 5 times more polyunsaturated fat. Wild game also contained EPA omega 3 fats, while our domesticated animals contain undetectable amounts. Eating large amount of your daily caloric intake from modern meat could lead to heart disease, obesity, and other diet related diseases. In the typical American diet, dairy, cereals, refined oils, refined sugar and alcohol make up 72% of calories consumed by Americans. The benefits seen in this diet are likely due to the substitution of refined oils and sugars with fruits and vegetables and not the elimination of food groups.
There is limited clinical research on the actual effects and benefits of this diet. One study showed improved diabetes control with a paleo diet. However, it did not control for critical factors such as total consumed calories. The paleo group consumed, on average, 500 calories less daily compared to the control group. Weight loss greatly affects diabetes control and may have accounted for the benefits instead of the foods incorporated with the paleo diet.
For athletes, especially strength athletes, the higher amounts of protein incorporated in this diet would be helpful if protein needs were not being met before since athletes have higher protein needs than non-athletes. However, athletes, especially endurance athletes, still need large amounts of carbohydrates, which are limited in this diet. If not consumed, the body will use protein as an energy source instead, which would limit the availability of the protein for strength and muscle gains.
In short, this diet has healthy components. However, it would be difficult to sustain and may be low on many nutrients due to the elimination of food groups. A better option would be to incorporate some principles of the diet, such as fresh whole foods, lean meats, nuts, and lots of fruits and vegetables, while still incorporating moderate amounts of dairy, whole grains and legumes which are nutrient dense and contribute many important nutrients especially for athletes.

o Position of the American Dietetics Association, Detitians of Canada, and the American College of Sports Medicine Nutrition and Athletic Performance. J Am Diet Assoc. 2009; 109: 500-527.
o http://www.eatriht.org
o Eaton B. S, Konner M. Paleolithic Nutrition. New England Journal of Medicine. 1985; 312:5.
o Cordain L, Eaton S. B, Sebastian A, Mann N, Lindeberg S, Watkins B. A, et al. Origins and evolution of the Western diet: health implications for the 21st century. Am J Clin Nutr 2005; 81:341–54.
o Jönsson T, Granfeldt Y, Ahrén B, Branell U, Pålsson G, Hansson A, et al. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovascular Diabetology 2009; 8:35.

• This reply was modified 10 years, 2 months ago by  Megan.

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