>It's not so simple. What you eat and your hormones determine the fat storage on your body.
It is, for the most part, but you're right; insulin spikes are a problem and you should not be gorging yourself on simple carbohydrates when on a diet. Of course, protein and fats can also contribute (ask any keto fan), so you have to eat in moderation and be mindful of your macros.
>Counting calories doesn't really work
Utter and complete nonsense. I have been actively monitoring and modifying my weight via calorie counting for more than two decades. I started boxing at 10, playing football and wrestling at 13, and to this day I still count calories and strength train at an intermediate competitive level ('competitive' in terms of what I lift in the big three at my weight, not to imply that I actually compete.)
I have helped many other people lose weight via calorie counting. It works, and to claim otherwise is simply ignorant. Of course quality of food is the next subject you broach with anyone trying to lose weight. No one should expect to lose weight and be healthy by eating 1200 calories of cake and another 500 in potato chips each day.
When you eat good food (increase your fat and protein as a % of your macros, stay away from processed sugars/carbs, increase your intake of vegetables, etc.) and limit calorie intake you lose weight. Speaking to most people in terms of insulin is a waste of time. They have no simple way to measure that, but if they eat under maintenance and eat generally good food they _will_ lose fat, and that's the goal.