Obesity Summed Up In A Single Rat Study

The mainstream view of obesity is that it is caused by consuming too much food and performing too little physical activity. This ‘eat-too-much, do-too-little’ theory of weight gain is widely accepted as fact amongst expert and layperson alike, however, the nutritional literature does not support this theory. In fact it is becoming increasingly evident from the literature that it is not how much food we eat that makes us fat, but the types of foods. Poor quality Western style foods devoid of meaningful levels of micronutrients and fibre, and the presence of metabolic poisons such as trans fatty acids and fructose, are now thought to contribute to the insulin resistance that drives weight gain and obesity. The erroneous assumption that weight gain is caused by too much food is followed by a similarly erroneous assumption that for weight loss to occur food intake must be curtailed. However, many studies in the literature attest to the ineffectiveness of this strategy, and it can be concluded from this evidence that calorie counting diets simply do not work.

The main problem with energy restrictive diets is that they cause a loss of skeletal muscle, and this then detrimentally affects the resting metabolic rate, making fat regain following any energy restrictive period inevitable. A rat experiment performed in the 1980’s sums up the main problems regarding the ‘eat-too-much, do-too-little’ approach to weight gain nicely. In the study1, rats were fed a ‘cafeteria style’ diet to fatten them, indicating that normal rat chow is not able to increase body weight in rats. This is likely a reflection of the fact that low quality foods must be eaten to cause weight gain and that rats will not overeat normal rat chow. This point is self evident to anyone who has ever kept a pet rat. Although there is ample food in the food bowl and the rat could eat whenever it likes, its body weight remain stable for life. This is an important point because it shows that low quality foods combining to make a poor quality diet are a requisite of weight gain and obesity, and that high quality nutrient rich foods are not obesogenic.

After the rats became obese on cafeteria style food, the rats were starved to cause weight loss. This simulated the calorie restriction seen in calorie counting diets, and based on the ‘eat-too-much, do-too-little’ paradigm, should have made the rats lean and healthy again. It is true that the rats did attain the same body weights as control rats fed normal rat chow. However, the body composition of the starved rats had changed considerably, and in particular the weight loss they experienced included a loss of lean tissue and water. In addition, the rats body fat levels remained elevated. When the formerly obese rats were then allowed to eat normal rat food again, these rats required less food to maintain their weight than the control rats and ad libitum eating caused the rats to remain moderately obese. Formerly obese rats also had an increased number of fat cells, although the fat cell volume was reduced. Therefore eating low quality foods increased the fat cell numbers in the rats and this increased number of fat cells remained following the energy restriction period.

Interestingly the formerly obese rats following starvation also spontaneously ate less than their control counterparts. This supports anecdotal evidence that those individuals with a history of repetitive cycles of calorie restriction often eat very few calories and still find it hard to lose any body weight. This suggests that the set point of normal energy regulation and appetite regulation has been altered and that the threshold for energy balance is much lower post-energy restriction. The metabolic dysfunction caused by a poor quality diet was highlighted by the fact that when overweight, the rats fed cafeteria style food developed insulin resistance. However, when they were fasted and returned to the body weight of control animals, the insulin resistance normalised. This supports the contention that obesity and weight gain is associated with insulin resistance, and that one of the possible drivers of obesity may be aberrations to the normal blood sugar regulation caused by low quality foods low in dietary fibre.

Dr Robert Barrington’s Nutritional Recommendation: Attempting to lose weight by restricting energy is foolhardy because like a moth to the light, no matter how many times it does not work, people return to this destructive practice. Energy restriction in the face of a metabolic abnormality causes further metabolic dysfunction that is now thought to be semi-permanent. Such yo-yo dieting is common and results in a downward cycle of deteriorating body composition. Eating high quality food and resistance training is the antithesis to the low calorie diet approach, the former having been shown to be an effective strategy to cause effective weight loss.


1Walks, D., Lavau, M., Presta, E., Yang, M. and Bjorntorp. 1983. Refeeding after fasting in the rat: effects of dietary-induced obesity on energy balance regulation. American Journal of Clinical Nutrition. 37: 387-395

About Robert Barrington

Robert Barrington is a writer, nutritionist, lecturer and philosopher.
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