The reason for obesity is not rocket science.

As this recent article in The New York Times points out, weight gain takes place when one consumes too many calories, and Americans are consuming more calories today than in the past. This increase in calories, not offset by an increase in activities and use of the calories, causes weight gain through storage.

We obsess and ruminate about what we eat, in the nonsensical belief that it matters when it comes to weight. Anyone who has taken a physics course understands the First Law of Thermodynamics: “Energy can be changed from one form to another, but it cannot be created or destroyed. The total amount of energy and matter in the Universe remains constant, merely changing from one form to another.”

In the case of calories, the energy is either used through metabolism or it is stored in the body and one gains weight. If one wants to lose weight, the solution is simple – consume fewer calories or use more energy. Whether the calories are consumed in carbohydrate, protein, or fat – it is calories being consumed. Whether one eats vegan, shops at Whole Foods, eats from their own garden, or buys fast food at McDonalds, one’s weight is a function of how many calories are consumed vs. used. “Healthy” foods don’t lead to health, and processed foods don’t cause damage if consumed in moderation.

The reasons that we consume more than we need are indeed complex and one can point to culture, government policy, marketing and more. These externalities can and do influence individual choice but in the end it is individuals who make the choice to consume. Obfuscating the reasons for obesity with delusions about diet is attractive to many. Education on the root cause is key to changing individual and social behaviors, and it starts with basic science.