A study analyzing all the research done on the eating habits of overweight people comes to this conclusion: overweight or obese people lie about how much they eat.

In the sense that when faced with questionnaires in which they have to reveal how much they eat, they tend to underestimate or not to mention the food actually consumed.

In short. According to this study, it seems that overweight people do not say how much they actually eat.

WHY DO OVERWEIGHT PEOPLE LIE ABOUT THEIR DIET?

According to Dr. Tracy Burrows, one of the researchers included in the study , there may be two reasons why overweight people end up lying about their diet.

• On the one hand, these people tend not to consider all those little snags or small bites of food they take between meals as a real meal. And that can actually seriously affect your daily calorie balance. For example, a piece of cheese while cooking. A biscuit tasted on the fly. A candy. This can happen either because they underestimate the calories of these small concessions, or because they eat without even realizing it, or they are “secret eaters” (they eat in secret).
  Worse when they eat out.
  They risk underestimating the calories of a hamburger, an ice cream, a first course.
• On the other hand, they may know what and how much they eat , but they prefer not to say it to appear more virtuous. So when faced with the questionnaires, overweight or obese people say they eat healthier than they do.
• Both of these behaviors make it difficult to assess their situation, understand what their problem is and find a practical solution to their overweight – worse when it comes to children or teenagers.

But that wouldn’t be the only thing people with weight problems lie about.
A previous study , also conducted by Burrows, showed how overweight people tended to lie about height, approximating it by one to two centimeters, and about weight, approximating it down.