Back in 2019
In 2019, I wrote a blog post about skipping breakfast. A review of clinical trials found that breakfasts that contained larger amounts of protein (30 grams of more), more energy (more than 350 calories), and which consisted of solid foods (as opposed to liquids) led to greater appetite control and satiety compared to breakfast skipping.
A systematic review and meta-analysis of 13 trials found that skipping breakfast predicted a small but significant reduction in weight (0.44 kg) compared to eating breakfast. However, of the included studies, I saw only one breakfast that I would consider “healthy.” Common breakfast items included packaged cereal, milk, and juice. In my view, these breakfasts included insufficient protein, fiber, fat, and calories. This meta-analysis compared the effects of eating a lousy breakfast or skipping it.
Physical activity after breakfast
A more recent study by British researchers investigated whether the timing of physical activity with respect to breakfast consumption affected post-meal interstitial glucose concentration (measured with a continuous glucose monitor). Forty-eight generally healthy, physically active adults were randomly assigned to one of three physical activity conditions: standing, walking, and circuit training, each for 30 minutes. Within each activity condition, participants completed four trials in random order. For Trial A, participants fasted overnight, arrived at the laboratory at 8 am, and immediately consumed a 500-calorie meal-replacement breakfast. After glucose was measured at 2 hours post-breakfast, the participants left the lab and completed their physical activity at some point later in the day. Trial B mirrored Trial A except that participants began their physical activity at 8am and consumed breakfast 30 minutes later. Trial C also mirrored Trial A except that participants completed their physical activity immediately after they ate breakfast at 8 am. Trial D was identical to Trial C except that participants completed their physical activity starting 30 minutes after eating breakfast.
Compared to Trial A (the non-active control condition), participants in Trial C (immediate post-meal physical activity) had significantly lower average glucose and lower total glucose over 2 hours post-meal regardless of the type of physical activity. Thus, 30 minutes of light- to moderate-intensity physical activity immediately following breakfast reduced the post-meal glucose spike and reduced glucose for 2 hours. After you finish your daily meals, can you find a way to move around for 30 minutes? How about a 30-minute after-meal walk following your biggest meal? If so, over time, you may reduce your risk of type 2 diabetes.
Late-evening snacking
Recent studies propose that the time of day you eat affects how your body processed the food you eat. Researchers at Vanderbilt University utilized data from six participants who spent two 56 hour periods in a whole-room respiratory chamber (except for two, 20-minute breaks) to test this idea. Fun, huh?! Instruments measured the changes in oxygen and carbon dioxide in the chamber arising from a participant’s metabolism. During one period, each participant ate dinner, and ate breakfast, lunch, and dinner over the following two days. During the other period, each participant ate dinner followed by a snack four hours later and ate lunch and dinner (but no breakfast) the following two days. The breakfast and the snack were nutritionally equivalent. The interesting finding: Eating a 700-calorie after-dinner snack about 7:45 pm dampened the body’s ability to metabolize fats compared to eating the equivalent amount and type of food at breakfast. Thus, eating breakfast, lunch, and dinner then avoiding after-dinner snacking might help people with overweight or obesity reduce their body fat.
Meal timing matters
Insulin sensitivity and blood sugar tolerance change during the day in response to circadian rhythms, with the optimal metabolic time occurring in early morning. Researchers in Europe used data from 103,312 participants with an average of 43 years in the NutriNet-Sante cohort to determine if meal timing predicted the risk of type 2 diabetes. After adjusting for confounding factors and compared to participants who reported eating their first meal of the day before 8 am, those who reported eating their first meal of the day after 9 am had a significant 62 percent higher risk of developing type 2 diabetes during a median follow-up of 7.3 years. Also, participants who ate dinner before 7 pm and who ate breakfast the next day before 8 am (equivalent to a 13-hour overnight fast) had a 53 percent lower risk of developing diabetes compared to other participants. Combining an early dinner with an early breakfast the next day might help manage blood sugar and maintain insulin sensitivity, thereby reducing the risk of type 2 diabetes.
More on meal timing
The timing and amount of food consumption relative to daily circadian rhythms appears to affect several measures of health. A recent review arrived at the following tentative conclusions. 1) Skipping breakfast may increase coronary heart disease, type 2 diabetes, hypertension, and obesity risk factors. 2) Eating breakfast earlier rather than later may reduce odds of the metabolic syndrome. 3) Eating lunch earlier may lead to better blood sugar control and lower insulin resistance. 4) Eating dinner later and eating more calories at dinner may increase risk of cardiovascular disease and the metabolic syndrome. 5) Increased day-to-day variability of the timing of breakfast and dinner may lead to higher body mass index, blood sugar, and inflammation.
Based on these findings, here’s an approach to healthy meal timing and amount. Eat a substantial breakfast at 7 am after arising, eat a more substantial lunch (the biggest meal of the day) at noon, and eat a modest dinner (the smallest meal of the day) at 5:30 pm. No food after dinner until breakfast. Alas, I have to figure out how to stop eating after dinner,
Breakfast suggestion
I recommend eating breakfast, but make it one that’s worth eating with quality foods that provide sufficient protein, fiber, and calories. My typical breakfast starts with a banana, then steamed veggies (either zucchini, or cauliflower, or broccoli) followed by a bowl of oatmeal made with a half cup of thick rolled oats and a quarter cup of wheat bran. I top the cooked oatmeal with half a cup of soy milk, ¼ cup of whey protein, a half cup of plain, lowfat Greek yogurt, a half-cup of fruit (either peaches, or pears, or frozen blueberries), and a dash of cinnamon.
