Check the Research on Whether Skipping Breakfast Makes You Gain Weight

Yet Korea's 2021 dietary guidelines include "Make sure to eat breakfast." Looking at what each source is actually measuring makes it easier to decide what to do with your own breakfast.

Where did the idea that skipping breakfast causes weight gain come from?

Quite a few observational studies have found that people who skip breakfast are more often obese. That is where the idea that eating breakfast helps with weight control spread from.

Observational studies struggle to separate out other habits of breakfast skippers, such as sleep, late-night eating, and work schedules. That is why the results of clinical trials that randomly assigned breakfast need to be looked at separately.

What did the review of randomized trials show?

Researchers at Monash University in Australia collected randomized trials in adults from high-income countries published from 1990 to January 2018. Of the 13 trials, 7 measured body weight and 10 measured daily energy intake.

People who skipped breakfast weighed an average of 0.44 kg less (95% confidence interval 0.07 to 0.82, I²=43%). People who ate breakfast took in an average of 259.79 kcal more per day (78.87 to 440.71). The energy results, however, varied widely across trials (I²=80%).

The researchers urged caution in reading the results. Every trial had a high or unclear risk of bias in at least one domain, and follow-up was short: an average of 7 weeks for weight and 2 weeks for energy intake.

Then why do the government guidelines say to eat breakfast?

The "Dietary Guidelines for Koreans," announced on April 14, 2021 by the Ministry of Health and Welfare, the Ministry of Agriculture, Food and Rural Affairs, and the Ministry of Food and Drug Safety, list "Make sure to eat breakfast" as one of nine rules. The same group includes "Avoid overeating and increase activity to maintain a healthy weight" and "Drink alcohol in moderation."

The dietary guidelines are recommendations designed for the eating habits of the whole population. The fact that breakfast skipping was not decreasing was presented as part of the background. The BMJ review asked whether adding breakfast helps you lose weight, so the two sources are answering different questions.

How should I decide on my own breakfast?

Looking only at weight, the evidence for forcing yourself to eat breakfast and for deliberately skipping it is weak either way. How much you eat over the whole day comes first.

• If you eat breakfast now, write down your breakfast menu and calories for about three days, and check whether your lunch and dinner portions get smaller.
• If you skip breakfast, use the same method to see whether it leads to morning snacks or overeating at lunch.
• If you decide to eat breakfast, check that it includes protein foods and vegetables and that you are not filling up on sweet drinks.

If breakfast fits your morning focus or exercise plans, there is no reason to skip it. On the other hand, if skipping breakfast leads you to binge at lunch, changing that pattern first matters more for your weight.

When should I talk to a professional?

If you have been prescribed blood-sugar-lowering medication or insulin, talk to your doctor before skipping breakfast. The same applies if you are pregnant or have ever been diagnosed with an eating disorder. This post does not replace a personal diagnosis or prescription.