Throughout recent history, we’ve gone through repeated cycles of dietary fads that shun certain types of food, including fats, carbs, and sugars. Corn Flakes, for example, were invented in 1894 as part of a low-fat diet craze, while the Atkins Diet, which shuns carbs and sugars, surged to popularity for the first time in 1974.

But are any of these dietary trends tied to real science about how what we eat affects obesity? A recent New York Times article explained that although diet has been studied extensively, there’s still not been a truly comprehensive, long-term study of the effects of diet on human obesity. We do have, however, a new study on mice that is shedding new light on the subject (and the results are surprising).

The Role of Fat In Obesity

A recent Cell Metabolism study followed lab mice on 29 different diets over a three-month period–which translates to a human being on a diet for nine years. The results even surprised the researchers: the only constant in the mice who became obese was a high-fat diet. In addition, mice on the high-fat diets also showed changes to their brains in the way that they processed rewards.

While this is only one study–and a study conducted on mice and not humans–it may show that consuming fat is closely linked to putting on fat, and while consuming sugars and carbs may have other negative health impacts, they may not be the main culprits when it comes to our waistlines.

Other Misconceptions About Obesity and Health

As research methods improve and our knowledge deepens, we are increasingly able to bust more and more myths about dieting and obesity. But even now, we have enough evidence to clear up some of the most common misconceptions. A 2013 special article in the New England Journal of Medicine outlined six such myths:

• Myth 1: Small changes in caloric intake or activity will result in large changes in body weight over time. In reality, making a small lifestyle changes can help you lose weight, but they won’t accumulate into large changes in weight as time goes by.
• Myth 2: It’s essential to set realistic weight-loss goals. Science actually shows that more ambitious goals are sometimes associated with better results, and that realistic goals don’t improve weight loss.
• Myth 3: Rapid weight-loss is associated with poor long-term results. Studies have shown that it isn’t necessarily bad to lose weight somewhat rapidly, when it comes to long-term outcomes.
• Myth 4: You have to be “ready” to lose weight. A study has found that if you would like to lose weight, you are ready enough to make changes.
• Myth 5: Physical education classes help prevent childhood obesity. While exercise surely affects the health of kids, in their current form, PE classes don’t significantly affect students’ BMI.
• Myth 6: Breastfeeding protects kids against obesity. While breastfeeding has other proven benefits, for mother and child, protecting kids against obesity has never been found to be one of them.

Two Constants: Activity and Moderation

Fad diets come and go–and even accepted science can change over time. But large bodies of research consistently point toward a combination of physical movement and moderation when it comes to health and healthy weight. Along with the busted myths above, it’s something to think about as the holidays approach.

References

1. Casazza, Krista. (2013). “Myths, Presumptions, and Facts about Obesity.” New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/NEJMsa1208051
2. Hu, Sumei. (2018) “Dietary Fat, but Not Protein or Carbohydrate, Regulates Energy Intake and Cases Adiposity in Mice.” Cell Metabolism. https://www.cell.com/cell-metabolism/fulltext/S1550-4131(18)30392-9
3. Reynolds, Gretchen. (2018) “Which Kinds of Food Make Us Fat?” New York Times. https://www.nytimes.com/2018/09/25/well/eat/which-kinds-of-foods-make-us-fat.html?