I don’t know, but when I went through Marine Boot Camp in early 1970 as a skinny kid I ate everything they put in front of me including fruit, fruit juices, sugar on buttered bread (pogey bait not allowed) and every fatty item them put in front of me. I only gained 15 pounds but I was fit and muscled when I came out, maintaining an ideal weight limits throughout a military career (not all as a Marine). Yes, exercise and reasonable eating habits will keep you healthy, if you have no other genetic or environmental causes such as smoking or exposure to high levels of various bad substances. I ate like a sumo wrestler most of my adult life while still maintaining good health and proper weight. When I hit my 50s my metabolism changed and I developed a belly roll despite regular exercise. When that happened I drastically trimmed my food intake, fat intake and cut out most sugars but it did nothing to trim my belly roll. My doctor simply says to keep at it and maintain my metabolic indicators (blood sugar, cholesterol etc); the belly roll may never go away.
That’s my point, 85-90% of all obese/over-weight people are that way due to lack of decent eating habits and obscene food intake.
I like to eat - I grew up on my grand-parent’s farm. We ate heartily! Biscuits, gravy, bacon, ham, eggs, pancakes, fried okra, fresh milk and butter, and orange juice (THAT WAS BREAKFAST)! But, we worked from 5:30AM until the sun went down! So, we were extremely active! I left the farm for my last three years at home (moved to the city), before joining the Corps, and I didn’t change my eating habits, but I definitely did NOT do nearly as much work and physical activity (even with high school sports). I quickly gained about 35 pounds.
About a year ago I realized that my work habits were causing me to have very bad eating habits and very little exercise time. My metabolism is pretty normal, if I am hungry, I eat. I try to exercise about 30-45 minutes a day (usually a short session in the morning and another in the afternoon). I drink LOTS of water. I have lost about 40 pounds in the last year or so. It is a pretty simple thing.
Now, if all you ever eat is sugary, fat filled cake and pies, as long as you work out in proportion to the intake, you can probably maintain your weight, but your body is going to be feeling pretty weak and bad - because you are not getting all the right nutrients and vitamins.
Same thing though, if you eat nothing but wheat-grass and drink water all day and only do “maintenance” work-outs, you will probably never be over-weight, but your body is going to be feeling pretty weak and bad - because you are not getting all the right nutrients and vitamins.
So, proper intake plus proper exercise usually equals normal body weight and healthy living! We each should know our own bodies and what we can eat and can’t eat, what work out works best for us and that which does not work. I don’t think people need to take 20 different pills, starve themselves and give up every single items that contains sugar. None of those things will fix weight issues: normal intake and normal exercise is the BEST way - PERIOD.