Obesity is among one of the larger public health challenges that the United States faces, with 20 percent of health-care spending going towards treating the disease and related conditions.

The New England Journal of Medicine recently took a look through some of the most commonly held beliefs about preventing obesity, such as the importance of physical education or realistic weight-loss goals. It found, perhaps disappointingly, that many of the obesity-prevention strategies we believe in have either been disproved in research, or have no evidence base at all.

Think eating breakfast will help you lose weight? There's absolutely no research to support that idea. What about small, sustained weight loss will lead to larger, long-term gains? Studies have found the exact opposite.

NEJM broke down solutions to obesity into myths — those that have been proven wrong in randomized, controlled studies — and presumptions, which have not been disproved, but also lack any research backing.

Here are the seven myths that, when they combed through the research, they found to be inaccurate.

Then there are the presumptions, about the importance of breakfast and the dangers of snacking, which are not currently supported by research — but have not been proven wrong either.

"Several presumptions appear to be testable, and some of them (e.g., effects of eating breakfast daily, eating more fruits and vegetables, and snacking) can be tested with standard study designs," the team of researchers write. "Despite enormous efforts promoting these ideas, research often seems mired in the accrual of observational data. Many of the trials that have been completed or are in progress do not isolate the effect of the presumed influence and the findings are therefore not definitive."