09 February 2011

Fast Food Diet, Sedentary Lifestyle and Insulin Resistance

Obesity and Type 2 Diabetes (T2D) are chronic diseases, meaning they develop over a long-period of time. There is an abundance of literature on type 2 diabetics having a history of being overweight or obese, prior to their diagnosis hence, it is wise for health providers to prescribe a lifestyle modification (in terms of diet, physical activity and stress management) that is geared towards disease prevention on a long-term duration. However, we learned during the Obesity/Diabetes class discussion that fat cells (also called adipocytes) behave like immune cells, capable of responding to short-term exposure to very high amounts of glucose from high carbohydrate diets, and excessive fatty acids from high fat diets. As long-term lifestyle modification starts from baby steps, I think it is interesting to know what happens to your body, specifically, the insulin response, when a person is subject to an acute (short-term) exposure to high carbohydrate and high fat diet via fast food.

A study by Danielsson et al. (2009) investigated the effects of overeating in fat cells of lean humans. The young adult subjects (average age was 27.3 years old) were fed a high calorie fast food diet twice a day for four weeks, with restricted physical activity of 5,000 steps a day. The intervention resulted in body weight gain of 10%, and an increase in body fat of 19%. Although the subjects remained of normal BMI (of normal weight for height) at the end of the study (baseline = 22.4, end of study =24.3), they exhibited moderate insulin resistance and reduction in insulin sensitivity.

In a separate study of young men and women (average age 26 years old), a treatment group was assigned to a four week fast food diet (twice a day)plus a sedentary lifestyle of not more than 5,000 steps per day (Astrand et al., 2010). The treatment group significantly gained weight after the intervention, and similar to the Danielsson study, showed increased insulin resistance and reduced insulin sensitivity. The insulin antagonist leptin and the acute inflammation marker C-reactive protein were elevated after four weeks in the treatment group.

Although both studies had small sample sizes (less than 20 subjects in each group) they provide direct application of what we learned in class – that overnutrition can metabolically stress the body which can lead to insulin resistance.

Realistically, it may be difficult to eliminate fast food meals completely from one’s diet. However, it is important to know how the body responds to an energy-dense diet on a relatively short-term duration, so that the next time one sees a glass of a 2,000-Calorie milkshake, one can make an informed decision as to how much should be consumed or whether it is smart to drink it at all, taking into consideration your usual diet and physical activity levels.

References:

Danielsson A, Fagerholm S, Ost A, Franck N, Kjolhede P, Nystrom FH, Stralfors P. Short-term overeating induces insulin resistance in fat cells in lean human subjects. Mol Med 2009;15:228-234.

Astrand O, Carlsson M, Nilsson I, Lindstrom T, Borga M, Nystrom FH. Weight gain by hyperalimentation elevates C-reactive protein levels but does not affect circulating levels of adiponectin or resistin in healthy subjects. Eur J Endocrinol 2010;163:879-885.

Mary Jo Cantoria

1 comment:

  1. I agree. Being fit and building more lean mass have health benefits that extend beyond weight management.

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