Meal Frequency and Timing and Related Changes in Body Mass Index (BMI)
A study published in 2017 in the Journal of Nutrition analyzed data from 50,660 adult members aged ≥30 y of Seventh-day Adventist churches in the United States and Canada (mean follow-up: 7.4 years ± 1.2 years).
It looked at the number of meals per day, length of overnight fast, consumption of breakfast, and timing of the largest meal. The primary outcome measured was a change in BMI per year. There was an adjustment for important demographic and lifestyle factors.
Not only are macronutrient composition and quality the only important factors of nutrition; meal frequency and timing are essential aspects as well
Excessive energy intake increases the risk of obesity and chronic disease, and obesity is a leading cause of disability and death in Western countries
A large proportion of the increased risk of obesity and chronic disease is related to aging
Eating more frequently and snacking are often recommended as a strategy for weight loss, as it is presumed to reduce hunger and, thus, energy intake and body weight
However, the widely held opinion that eating more frequently is better for weight control than eating larger meals less frequently is not as scientifically well-established as is believed
Some observational studies have suggested that people who consumed more snacks were less likely to be obese, but other large prospective studies seemed to have shown that frequent snacking leads to weight gain, increased abdominal and liver fat, and an increased risk of type 2 diabetes mellitus; not only because of the higher energy intake mainly from added sugars, but also because of increased food stimuli, hunger, and the desire to eat
In keeping with this, reduced meal frequency can prevent the development of obesity and chronic diseases and extend life spans in laboratory animals
Mice under time-restricted feeding consumed equivalent calories from a high-fat diet as those with spontaneous access yet were protected against obesity and diabetes
Intermittent eating and fasting lead to a prolonged life span and positively affect glucose tolerance, insulin sensitivity, and incidence of type 2 diabetes in mice
The effect of meal frequency on body weight in humans has not been studied extensively and in only a few randomized clinical trials.
These trials typically included small numbers of participants (maximum of 40 subjects), were only short-term (maximum of 8.5 weeks), and varied greatly in meal frequency manipulations with a range of 1 to 12 meals per day
Some research suggests that the higher consumption of protein more frequently may be beneficial in overweight subjects
Results suggest that in relatively healthy adults, eating less frequently, not snacking, consuming breakfast high in protein, and eating the largest meal in the morning may be effective methods for preventing long-term weight gain. Eating breakfast and lunch 5 to 6 hours apart and making the overnight fast last 18 to 19 hours may be a sound, practical strategy
Kahleova H, Lloren JI, Mashchak A, Hill M, Fraser GE. Meal Frequency and Timing Are Associated with Changes in Body Mass Index in Adventist Health Study 2. J Nutr. 2017 Sep;147(9):1722-1728. doi: 10.3945/jn.116.244749. Epub 2017 Jul 12. PMID: 28701389; PMCID: PMC5572489.