I know that diet/exercise goes hand to hand and everyone should implement both. But can you be healthy without exercise? Or exercise is a cheat code to be healthy?
There are things exercise can do better than diet. There are also things exercise can do that diet cannot do at all. For example, aerobic exercise can increase mitochondrial density (the increase in size and number of mitochondria). Resistance training can increase bone mineral density and skeletal muscle mass (some of the metabolic benefits of improved body composition are unlikely to be replicated to the same extent by nutrition alone).
You could probably live in decent health from diet alone for a while. But being sedentary will catch up to you as you age, increasing the risk of falls due to frailty, sarcopenia, osteoporosis, etc.
Exercise is more important than diet. It’s probably the most important thing you can do for your body besides sleep.
And let me hedge all the “you can’t outrun a bad diet” idioms. It’s not about losing weight through exercise. You should be exercising regardless
Increasing muscle density improves bone density, increases glycogen disposal, makes your body more insulin sensitive. Cardiovascular training lowers your blood pressure, your heart rate, improves blood flow. Exercise improves digestion, sleep quality. Exercise reduces risk of all cause mortality whether CVD or otherwise.
Fat or thin, you should be exercising first, focusing on diet second.
Exercise is important to the extent that you need to be somewhat active. If you have job that involves sitting still alot, you’d need to incorporate a work out routine. If you have an active job, you’re good. A lot of jobs are in between. Kind active in the since you walk alot or half desk half activity. You may want to add something extra for those.
Exercise alone will not give you good health. A gym “bro” that eats like crap will have issues sooner or later
Diet is ultimately the most important thing for health. You can not be healthy while eating chips, pizza, and fast food everyday. Your body requires vitamins and minerals that are not in or have been removed from most of these foods.
Good Diet alone isn’t enough for health. If you eat great but get tired walking your dog, not so good
Diet and activity. You can eat well and not exercise and be healthy but you can’t be sedentary on a couch and depressed. Exercise is used not just for muscles but mood, using your body does wonders. And you can eat poorly(not badly) exercise and be healthy.