The energy balance theory of weight loss suggests that changes to body fat levels in humans are caused by changes to energy balance. In this regard increasing energy intake and decreasing energy expenditure, creates a positive energy balance and this then causes weight gain. In contrast, so we are told, decreasing energy intake and increasing physical activity creates a negative energy balance and this then causes weight loss. However, this theory has been extensively questioned for its over simplicity, as it does not take into account other avenues that animals possess to expend or conserve energy, many of these regulated subconsciously by the hypothalamus. In addition, the theory does not take into account that weight gain may be a disease characterised by metabolic dysfunction centering on the development of insulin resistance. That many studies have been performed that disprove the energy balance theory of weight change, has however done little to derail it as the current mainstream paradigm.
That additional energy expenditure does not cause weight loss has been well evidence in the scientific literature. Many well designed studies have shown no weight loss benefit to physical activity. For example, one study1 investigated the effects of a playing video game that required physical input for 1 hour in order to participate. This was compared with a seated no video game and seated video game playing control period. This video game exercise was then followed by an ad libitum meal and energy expenditure was monitored through portable indirect calorimetry devices and food intake was monitored with food diaries over the same 3 day period. The results of the study showed that activity within the video game period was 144 % higher than resting or seated control periods, but no significant differences in energy expenditure over 24 hour period were observed between conditions. There was also no compensatory energy intake in the subsequent ad libitum meal and appetite sensations were similar between groups at all times.
These results support many other studies that show that increases in energy expenditure can be offset at a later time point with compensatory behavioural and physiological changes that preserve energy and so redress that energy balance. This suggests that the energy balance theory of weight gain is not correct and is not supported by observable scientific data. If it is true that increases in energy intake and decreases in physical activity do not cause weight gain, then the question as to what causes these changes must surely be addressed. In this regard, it is becoming increasingly evident that long term weight gain and obesity are a symptom of disease, and reflect an underlying metabolic dysfunction caused by poor quality food. This food creates a metabolic dysfunction that centres on the development of insulin resistance, and under these conditions, the normal compensatory mechanism used to balance energy do not function correctly. This then leads to a gradual accumulation of energy as body fat.
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