Breakfast eaters do have a lower risk of obesity. Breakfast skipping is associated with weight gain in observational studies. When we look at studies comparing breakfast eaters to non-breakfast eaters, the research suggests that skipping breakfast greater than 3 days per week is associated with an 11 % increased risk of obesity compared to breakfast eaters. This suggests that for the prevention of obesity, eating breakfast seems to be important. Physiologically this makes sense in that breakfast is the meal typically consumed after the longest fasting period in a 24-hour cycle. There is an associated decrease in ghrelin which is an appetite hormone and an associated increase in energy expenditure after breakfast eating. We are also learning that the circadian rhythm and light and dark cycles influence metabolism and presumably the propensity to store fat. There is an association between breakfast skipping and the development of metabolic problems such as Type 2 Diabetes. In intervention studies, delayed eating (i.e., the majority of calories later in the day) was associated with weight gain and changes in biomarkers associated with metabolic dysfunction such as insulin. The bottom line is that breakfast eating for weight gain and obesity PREVENTION may be important. Interventional studies reveal if we take a non-breakfast eater and then introduce a daily breakfast, that is actually associated with weight loss. This has to do with the satiety, energy expenditure and metabolic impact of a healthy breakfast. Of course, the quality of this breakfast matters as well.

What about the intermittent fasting and time-restricted eating trend? Intermittent fasting is well supported in the literature as a weight loss strategy. The prolonged fasting seems to carry additional metabolic benefits meaning it is not just the lower calorie count that helps with weight loss. Those who go from breakfast eating to delaying breakfast will lose weight in part because they are consuming less energy in the twenty-four-hour period but also because of the metabolic benefits of the prolonged fast. I notice that sometimes when I am discussing time-restricted eating with patients, occasionally someone will say “well, I do that naturally anyway”. For those people already with a delayed eating pattern, this strategy will not work, and circadian metabolic disturbance may be part of weight loss resistance. In observational studies, for some people, moving the fasting period to the evening rather than in the morning works a bit better for weight loss. The bottom line is that when breakfast eaters start to delay the first meal of the day, there is associated weight loss in intervention trials.

What can be taken from all this conflicting evidence in the literature? Well, if you are a breakfast eater, maybe you want to try time-restricted eating and delay the first meal of the day by skipping breakfast and consuming food only between 12 pm – 6 pm which would yield an 18-hour fast. In this scenario, less calories will be consumed, and you will be extending the overnight fast which has some metabolic benefits including reduced inflammation and a drive to burn fat for energy. If you are not a breakfast eater, maybe the next step is introducing breakfast each day which may impact metabolic rate, activity, and fullness throughout the day. Another strategy could be to use time-restricted eating but choose to place the eating window in the morning and stop eating early to extend the overnight fast. This may give the benefits of both intermittent fasting and breakfast eating. As with most things, these strategies for weight loss must be tailored to the individual.