Is taking breakfast beneficial for reducing weight?

Maybe, you have been told to take breakfast for your health. The contents of breakfast are consumed for the energy of daily activity. If you do not have breakfast, your brain will not work properly. And, omitting breakfast will make you obese.

Such ideas are, however, quite doubtfully supported by the evidence. It is said taking breakfast campaign is a produce of companies selling cereal, or oven toasters. I am not sure about it, but indeed, the effect of taking breakfast is still under investigation.

The New York Times: Ask Well: Does Skipping Breakfast Cause Weight Gain?

Research about nutrition is difficult because clinical trials are rarely conducted in this region. We have much data about the relationship between fasting on the morning and obesity. But it cannot be a causal relationship. Fasters may have some bad habits to weight gain. Their lifestyle is often unhealthy: getting up lately, smoking, taking alcohol, less physically active, and having some illnesses.

A newly developed study suggests that taking breakfast has no effect on body weight. In this study, participants were randomly assigned to breakfast group or fasting group. They were examined in detail at the beginning and after six weeks of trial.

American Journal of Clinical Nutrition: The causal role of breakfast in energy balance and health: a randomized controlled trial in obese adults

These results look persuasive at a glance. Unfortunately, however, I think there are some flaws in this trial. Firstly, the sample size is too small. In the trial to prove the significant difference, sample size should be minimized with statistical analysis. But in this study, no significant difference in body weight change between groups was observed. It does not mean that exactly there is no difference. Examining the equality of two groups demands larger sample size, and it has been examined yet in this study. Secondly, I am doubtful that participants completely changed their lifestyle during the trial. Taking breakfast is a habit not easy to change. Thirdly, it is unsure that observational term is adequate. Six weeks seem too short to affect body weight and some other indicator in the body. And finally, 700 to 1100 kcal is obviously too much for intake as breakfast. It may be usual in the UK. But I think very few Japanese take 700 kcal in the morning.

On the other hand, in this study, it is reported that insulin responsiveness has changed in both groups. Fasting caused increased insulin releasing. It potentially leads to metabolic syndrome. In this paper, this finding is emphasized, but newspaper article omitted this fact. It seems biased.

After all, I believe taking breakfast is rather beneficial though its magnitude is small. I recommend you to eat something not delayed in the morning.