Small, frequent meals is a dietary pattern characterized by consuming multiple meals throughout the day. This dietary pattern has been on a rise, thanks to aggressive marketing of snacks, decline in home-meal preparation, longer waking hours, among other reasons. But aside from convenience, does consuming 6 to 8 or even 10 meals per day instead of the traditional 3 meals per day confer health benefits?
It was commonly believed that having many small meals per day increases satiety. Supporting this notion are cross-sectional studies suggesting an inverse association between eating frequency and body weight in adults(1). Meanwhile, data from the NHANES suggest a positive association between eating frequency and energy intake in the healthy US population, whereby each additional ‘eating episode' is estimated to contribute an additional ~200 kcal to overall energy intake potentially resulting in weight gain in the long-term (2). These findings, however, are greatly hindered as a result of under reporting of energy intake and meal frequency, particularly among nibblers (3).
The relationship between meal frequency and weight loss in overweight and obese individuals is also limited. A randomized, controlled trial in 2012 identified no differences in energy intake and BMI between participants randomized to either three or five meals per day (4). These findings were similar to other trials as well, which suggest no weight loss benefit from frequent meal intake (5). Meanwhile, in the healthy elderly, grazing may ensure adequate energy and micronutrient intake (6,7). While the contribution of small, frequent meals on energy balance remains equivocal, its influence should further be examined in the context of dietary quality and achieving adequate micronutrients intake.
Clinically, ‘small, frequent meals' is perhaps the most commonly used medical nutrition therapy. Clinical nutrition guidelines generally recommend six to ten meals per day for patients experiencing early satiety and anorexia as they battle various diseases, such as pancreatitis and gastroparesis, or undergoing appetite suppressive treatment, such as chemotherapy, as recommended by the American Cancer Society(8). This eating pattern promises to decrease bloating, overcome early satiety and other symptoms, to help achieve adequate caloric intake (9). Grazing is also indicated post surgery for many gastrointestinal procedures including bariatric surgery and Whipple, to accommodate calories without abdominal distention and discomfort or dumping syndrome. Despite its short-term benefits, prolonging this dietary pattern post surgery may result in adverse health outcomes, such as less weight loss and eventual weight regain following bariatric surgery (10). These findings support the notion that this eating pattern more likely than not contributes to positive energy balance in the long-term. Yet this remains under examined, and whether the provision of small, frequent meals does indeed result in increased caloric intake in nutritionally at-risk individuals, such as those with pancreatitis, has yet to be elucidated.
An often-overlooked consequence of grazing is curtailed fasting duration. Clinical indications of small, frequent meals also include avoiding prolonged fasting, which is critical for cirrhotic patients, for example, to overcome the onset of endogenous protein breakdown for gluconeogenesis particularly during nocturnal fasting. However in healthy individuals, nocturnal fasting has been shown to provide various health benefits .
Several hurdles remain to be overcome in advancing our understanding of the relationships between grazing pattern and health. Among the most pressing limitations is the consistent use of a single definition for ‘meals' for meaningful comparisons among studies. In addition, appropriate assessment tools, such as multiple food diaries –capturing meal size and time – in addition to nutrient intake, instead of food-frequency questionnaires should be adopted moving forward to accurately assess frequency.
The 2010 Dietary Guidelines of Americans concludes that there seems to be inadequate evidence to accurately evaluate the relationship between meal frequency and nutrient intakes. The current evidence does seem to suggest that unless clinically indicated, perhaps the general population should follow a more structured, 3 nutritious meals at regular times per day because of difficulty related to achieving energy balance without proper portion control. In addition, small, frequent meals often tend to be in the form of convenient snacks, which contribute refined carbohydrates, rather than fats and proteins, to the diet, and therefore add minimal nutrition to the diet for the most part. Thus, if necessary, provision of this dietary pattern should also be supplemented by an education focused on healthy meals/snacks and portion control.