This is just a casual observation:
I tend to believe that to lose weight, keep a healthy weight and to have healthy lifestyle long term, does mean taking a greater interest in cooking and food in general. Not just mindless cooking or grocery buying without thinking.
A woman at work is obese --she does need to lose over 70 lbs. or so. (A sister of mine lost 50 lbs. So I know what 50 extra lbs. looks like.) She has difficulty walking and does pant if one walks too quickly in the office with her. Once she fell down during the workplace fire drill, merely because of this walking difficulty. It upset her that she cried. (She is 50 yrs. old.)
She has hinted that her weight problem is hereditary. Maybe. During our annual Christmas luncheon, she ordered what was probably perceived as healthy/yummy for her: a dinner size plate amount of...macaroni and cheese. This was at a beef, Canjun food type restaurant.
For a potluck luncheon, she brought in a leafy salad with shredded cheese, etc. Hardly anyone touched it. During a conversation she declared to me loudly, that she didn't like cooking. Ok. (Sometimes people declare this to disassociate themselves from a domestic activity.) I only responded that I did stir fries while dearie was great at making up salads.
Honest, she probably doesn't know/want to cook differently but maybe wants to or is trying to. I hope she is, for the latter.
Most people I know who have maintained a healthy weight or have lost weight, do take an interest in their food-buying and cooking. I'm refering to people I've known for the past 3 decades or more.