It’s not about willpower
I have a number of clients whose significant other (in my clients words)…
“Is able to eat anything without gaining weight”
“Is 6 foot tall and race horse lean and able to eat as much as they want”
“Can just leave chocolate in the fridge for days or weeks”
“Will choose to eat fruit even when there’s cake just sitting there”
And when these significant others see my clients struggling with food and weight, they may say things like;
“Just don’t eat as much”
“Just don’t buy it”
“Are you sure you really need that?”
“Wouldn’t you be better of having…”
“Just put it somewhere you can’t see it”
“It’s not rocket science, just eat a bit less and move more”
With regard to the first round of statements, if a person happens to have a smaller or leaner body type (due to genetics), then they may never have felt the need (or pressure) to restrict food. They may never have had anyone (such as a parent or other relative) restrict their food or suggest “you shouldn’t eat that”.
The reason they can leave chocolate in the fridge or choose fruit over chocolate has less to do with willpower and much more to do with never having been truly restricted of food, or made to feel “bad” about eating food. Deprivation drives desire and it is the restriction of food (both physically and mentally) that so often leads to over-eating or feeling like you’ll never stop once you start.
The notion that these people can “eat anything they want” without gaining weight is because they have permission to eat anything they want, again, they haven’t been restricted, they (often) literally eat whatever they feel like. That said, not everyone in a smaller body allows themselves to eat freely, some will still “be careful” or restrict certain things. Some of these people are being unnecessarily careful and with some, it may be helping them stay smaller, however these people have genetically smaller bodies to begin with. The combination of not being in a state of constant food restriction (or having the belief that you should be restricting) and a genetically smaller body, means these people don’t face the same struggle with food that others may face.
With regard to the second round of statements, if someone close to you says these (or you are this person), please understand they although they are usually said with the best of intentions, they are unhelpful and misguided for the reasons explained. Unfortunately we live in a culture that continually validates this way of thinking without stopping to question why so many people struggle with food in the first place. If you want to discover a different way of thinking, you might like to learn about intuitive eating. Often these significant others are intuitive eaters.