Reducing Calories Will May Not Help Losing Weight

As the widespread availability of highly calorific food has resulted in a high incidence of obesity, attempts to decrease body weight have concentrated on trying to reduce energy intake. It is suggested that this is not the best approach. Although consuming more calories than expended is part of the initial problem, it does not follow that reducing intake, unless consciously counting calories, is the best solution.
 
Mechanisms smooth out the large day-to-day differences in energy consumption, decreasing the importance of the size of a meal. In the short term, a reduction in energy intake is counteracted by mechanisms that reduce metabolic rate and increase calorie intake, ensuring the regaining of lost weight. For example, even a year after dieting, hormonal mechanisms that stimulate appetite are raised. Over a million calories are consumed a year yet weight changes to only a small extent there must be mechanisms that balance energy intake and expenditure.
 
As obesity reflects only a small malfunctioning of these mechanisms, there is a need to understand the control of energy balance and how to prevent the regaining of weight after it has been lost. By itself, decreasing calorie intake will have a limited short-term influence.
 
As it predisposes to many diseases and decreases life expectancy, the increasing incidence of obesity is among the greatest problems facing the human race. By 2025, 18% of the world’s male population and 21% of women will be obese. In the United States, 68% are already classified as overweight or obese. Attempts to reduce obesity have focused on reducing calorie intake, but has too much time been spent looking the wrong way down the telescope? Is reducing calorie intake likely to fail as it ignores the mechanisms that the body uses to maintain its existing weight?
 
Psychological interventions have in common that they attempt to reduce calorie intake, for example trying to regulate appetite, increase satiety, or reduce portion size. It has been claimed that “portion size is a modifiable determinant of energy intake that should be addressed in connection with the prevention and treatment of obesity. It has been said that “foods that target within-meal satiation and postmeal satiety provide a plausible approach to weight management. Alternatively, the effort has been directed at understanding appetite, although a systematic review failed to find an association between appetite and energy intake.
 
Trying to reduce calorie intake is also the fundamental principle that directs much of public health policy. The U.S. government dietary guidelines suggest that we should “Avoid oversized portions.” In addition, the number of calories is printed on food labels and lower-calorie options are widely available in supermarkets. The U.K. policy on healthy eating suggests “putting calorie information on menus” and “helping people to eat fewer calories (for example by changing the portion size or the recipe of a product).
 
However, obesity demands a more sophisticated approach than counting calories: It needs to be treated as an interdisciplinary topic. Those giving psychological advice need to be cognizant of aspects of both physiology and nutrition: Their recommendations must be compatible with bodily predispositions.
 
Biologists have tended to examine physiological mechanisms that influence energy balance. For example, the hypostatic hypothesis suggests that a centre in the hypothalamus monitors metabolites in the blood and, using feedback mechanisms, attempts to balance energy intake and expenditure. The approach gained a boost with the discovery of leptin, a hormone released from adipose tissue that reduces hunger.
 
In contrast, psychologists typically expect the level of body fat to reflect aspects of the environment, food intake, or lifestyle. The present argument is that the interdisciplinary nature of obesity demands both approaches. There are interactions between physiology, the environment, and psychology. More specifically it is argued that having a reduction in calorie intake as the central plank of an antiobesity strategy fails to acknowledge the existence of physiological mechanisms that predispose to its failure.
 
Psychologists interested in reducing obesity should consider altering their approach. Why is a reduction in calorie intake recommended when a lower energy intake leads to hormonal changes that stimulate appetite reduce metabolic rate and stimulate the consumption of more calorific foods? Although it may appear to be common sense to suggest that eating less will reduce the risk of putting on weight, this may not be the optimal approach.
 
As the approach taken by psychology is to reduce caloric intake, various questions are considered. How does the body respond to a small change in the caloric content of meals? How does obesity develop? What nutritional approach should be taken rather than simply concentrating on the calorie intake? Finally, in the context of the resulting conclusions, how should psychologists study obesity?