Meal timing, what do we know?
The Nutrition Society Paper of the Month for November is from Nutrition Research Reviews and is entitled ‘When to eat? The influence of circadian rhythms on metabolic health: are animal studies providing the evidence?‘. Authors Sofía Moran-Ramos, Adrian Baez-Ruiz, Ruud M. Buijs and Carolina Escobar present the background and key findings to their paper below.
‘Breakfast like a king, lunch as a prince, dine as a pauper’; this ancient folk wisdom is recently receiving support from scientific research showing a strong relationship between circadian rhythms and metabolism. Indeed in the last decade there has been an increasing recognition that meal timing is important to metabolic health, and that inadequate timing of food intake could be contributing to the worldwide epidemic of obesity.
Most, if not all organisms show circadian rhythms, which are daily fluctuations that follow a 24-hour cycle in physiology, mental and behavioural abilities, responding primarily to light and darkness in the environment, for us, day and night.
Thus circadian rhythms have a profound influence on metabolic processes. Recent findings indicate that food intake should be synchronized with the time signals provided by the master clock in our body, the suprachiasmatic nucleus (SCN), in order to elaborate efficient responses and optimize energy use and storage. Indeed, desynchrony of meal timing from the SCN signals, as in night/shift workers, who modify their food intake towards the night, show that they have a greater risk for the development of obesity, and metabolic diseases.
But what do we really know about it? This review examines the evidence of animal studies, to give an overview of the state of the art on metabolic findings and to assess whether the paradigms used in rodent models give the evidence to support a ‘best time’ for food intake.
So far animal studies correlate well with human studies, demonstrating that restricting food intake to the active phase limits adiposity and metabolic disturbances produced by high-energy diets. In contrast, eating during the inactive/sleep phase leads to greater adiposity, and in the long term to fat accumulation in the liver. The mechanisms while still unclear; could be related to decreased thermogenesis, and the gut microbiota could provide additional mechanisms.
Animal studies agree that within the active phase, breakfast is a ‘better’ time for food intake, limiting the impact of high calorie diets. Breakfast eating is accompanied by an improved metabolic plasticity, to use fat as the energy substrate, which may contribute to the observed effect. So after all the ancient wisdom of ‘Breakfast like a king, lunch as a prince, dine as a pauper’ could hold also in animal studies some truth.
The full paper ‘When to eat? The influence of circadian rhythms on metabolic health: are animal studies providing the evidence?‘ is freely available until the 10th December 2016.
Nutrition Society Paper of the Month
Each month a paper is selected by one of the Editors of the five Nutrition Society Publications (British Journal of Nutrition, Public Health Nutrition, Nutrition Research Reviews, Proceedings of the Nutrition Society and Journal of Nutritional Science).