The development of obesity is not fully understood, but it is generally considered to be multifactorial in aetiology. In Western nations cases of obesity are rising and evidence suggests that lifestyle and dietary habits are contributing to this epidemic. The traditional medical view is that weight gain is caused by a positive energy balance that results from too high an energy intake coupled to too low and energy expenditure. However, science has failed to conclusively prove that increasing energy expenditure or decreasing energy intake can effectively maintain long-term weight loss in obese individuals. Recently, the focus of research has shifted to identify dietary and lifestyle factors that may cause metabolic dysfunction that could result in weight gain. Meal timing, frequency and regularity have all been extensively studied in order to find their association with weight gain.
For example, research1 published in the American Journal of Clinical Nutrition in 2005 investigated the effect of meal regularity on various parameters that are thought to contribute to obesity. In particular, the researchers were interested in the effect of regular or irregular meal patterns on insulin sensitivity, thermogenesis and fasting lipid profiles. Ten women with a mean body mass index of 37.1 kg/m2 were fed their normal diets, but assigned to either a regular meal pattern (6 meals per day) or an irregular meal pattern (3 to 9 meals per day). After 14 days, the women crossed-over to the other meal regimen. The results showed that regular eating was associated with lower energy intake, a greater postprandial thermogenesis and lower fasting total and LDL cholesterol. Peak insulin concentrations as well as area under the curve of insulin response to the meals were higher after the irregular meals.
The irregular meals patterns chosen for this study were designed to simulate the meal irregularity that may result from a chaotic lifestyle as found in some individuals in modern developed nations. The results showed that the regularity of eating pattern affects some of the physiological parameters that are linked to obesity. In particular, the regular meal pattern increased postprandial thermogenesis and decreased energy intakes, suggesting that regularly spaced meals would be more likely to cause a negative energy balance. While the weight gain seen from both decreased thermogenesis and increased energy intakes would not be significant in the short-term, over the long-term they could contribute substantially to the development of obesity. The detrimental changes to the lipoprotein levels seen in the subjects eating irregular meals also suggests that this pattern of eating increases risk for developing cardiovascular disease.
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