“Many — if not most — studies demonstrating that breakfast eaters are healthier and manage weight better than non-breakfast eaters were sponsored by Kellogg or other breakfast cereal companies whose businesses depend on people believing that breakfast means ready-to-eat cereal.”
…These observational studies generally took people who were already eating breakfast and then compared them with people who weren’t. They weren’t experiments that randomly assigned people to eat breakfast or not and compared the difference.
That means breakfast itself may not account for differences in bodyweight or disease between the two groups. People who eat breakfast might differ in other ways from those who don’t. Maybe people who exercise are more likely to eat breakfast, and that explains the difference. Or maybe it’s a function of income. It’s hard to tell.
…The BMJ published a systematic review of 13 randomized controlled trials, including the big 2014 study. They concluded that there’s “no evidence to support the notion that breakfast consumption promotes weight loss or that skipping breakfast leads to weight gain.”
Instead, the people who ate breakfast consumed 260 more calories per day and weighed a pound more than the breakfast skippers, so “caution is needed when recommending breakfast for weight loss in adults, as it may have the opposite effect.
…The breakfast studies also don’t pay enough attention to the quality of food people are eating, obesity doctor Yoni Freedhoff has pointed out. “What a person eats for breakfast will matter a great deal, and just studying whether or not a person ate breakfast, will lump together bowls of Froot Loops with almond topped steel cut oats, and Pop Tarts with summer vegetable omelettes.”
…There was some compelling evidence to suggest undernourished kids perform better at cognitive tests when enrolled in a breakfast program. But it wasn’t clear that the breakfast itself was doing the trick — it might have been the fact that the program led to increased school attendance.