@Zoltariel – Not necessarily. Hormones change with age. All my hormones levels dropped dramatically after age 30. I’m a woman.
I went from 123lbs at 23% body fat to 140lbs at 30% body fat within 2 years, in spite of eating well and being very active. After fighting it with no results for years of intense interval training, Crossfit, weight training, firefighting training & nutrition (it doesn’t get more hardcore and strict than firefighting, except maybe military), all guided by personal trainers, naturopaths, doctors, nutritionists, and with regular professional lab results (blood panels, etc), I lost exactly 1% bodyfat and gained no lean mass. Professionals were stumped. I could lose a year’s progress within a week of slacking off. The same effort in my 20s would have given me 6 pack abs within 1 month.
And no one who hasn’t experienced it will believe it.
I assure you I’m experienced and educated in exercise and nutrition, with a background in kinesiology and used to be a fitness model in my 20s.
Telling these people its just a matter of “calories in vs calories out” is an infuriating and gross simplification. Not to mention that 1200cal per day and moderate to heavy exercise (as recommended by many “professional” diet services to deal with stubborn weight) actually makes things worse, not better. It wasn’t until someone looked at my hormones and I got a prescription (in my case, for low dose DHEA) that my body started slowly responding to my exercise & nutrition again. But doctors mostly don’t take premenopausal women’s hormone imbalances seriously. I had to advocate for myself in the medical system and pay out of pocket for years (thousands of dollars per year) to get it addressed. I’m 37 now and only just starting to see results at last.