Meal timing and frequency: implications for cardiovascular disease prevention A scientific statement from the American Heart Association

Irregular eating patterns appear less favourable for maintaining body weight and optimal cardiometabolic health. This was investigated in a comprehensive review analysis that evaluated the effect on body weight and cardiometabolic health of consuming breakfast, fasting, eating frequency and timing.

Although more direct translational research is still needed, the data suggested that intervening on meal timing and frequency may be beneficial. The clinician’s goal may be to help the patient spread energy intake over a defined portion of the day in a more balanced way rather than limited to one segment of the day or continuously over long periods of time. This does not mean that total energy intake and macronutrient balance can be ignored but simply that the frequency and timing of intake are the basis for building the structure for intentional eating.

More specifically, the review analysis of epidemiolocal studies provided strong evidence of a relation between breakfast skipping and cardiometabolic risk. Skipping of daily breakfast was associated with low nutritional adequacy of adult diets, adiposity, more cardiovascular disease (CVD) risk factors and markers of impaired glucose metabolism. Furthermore, two prospective studies showed a greater risk of CVD when skipping breakfast. In addition, clinical intervention studies suggested that skipping breakfast has limited impact on weight loss, as the lack of nutrients is often compensated during the day.

In respect to fasting, it was found that both alternate-day fasting and periodic fasting may be effective for weight loss, although there were no data that indicate whether this loss can be sustained long-term. With these regimes, triglyceride levels lowered but not total-, LDL-, or HDL cholesterol levels.

Several epidemiological studies related to eating frequency had different conclusion, although greater eating frequency seemed to be related to improved CVD and diabetes mellitus risk status. Moreover, intervention studies in which frequency was changed under isocaloric conditions did probably not decrease body weight or improve traditional cardiometabolic risk factors.

The impact of timing, particularly related to the evening meal, deserves further study. Epidemiological findings suggested a potential detrimental effect of late meals on cardiometabolic health, but clinical intervention studies have been limited in scope and too diverse to draw definitive conclusions.

Research related to these topics may be hampered by the lack of consensus on the definition of a meal, snack and meal timing. The authors proposed that eating occasions be defined as any eating/drinking episode providing at least 210 kJ and that 15 minutes should be the minimum amount of time elapsed between separate occasions. Distinguishing between meals and snacks should be left to the participant’s discretion.

The patterns of meal and snack eating behaviour have changed over the past 40 years. The traditional breakfast-lunch-dinner pattern was often not observed in a population of healthy, non-shift-working adults. Because feeding and fasting entrain clock genes, which regulate all aspects of metabolism, meal timing can have serious implications for the development of CVD, type 2 diabetes mellitus and obesity.

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