>>1617609If you're just sitting at home all day, you can subsist on very low levels of food. Exercise can help speed up the process if you are too stuck in the habit of eating regularly. At a brisk walking pace, you would burn 100 to 300 calories in 30 minutes. Some of those calories will be from stored fat. During the first 30 minutes of exercise, your body is mostly burning sugars that are hanging out in your blood and liver. But if you do the walk first thing in the morning, the calories will come from your fat reserves moreso, as your blood sugar will be lower before breakfast.
Energy in/energy out is the final word, of course. You could just not eat 300 cals instead of walking for 30 minutes. Some people literally cannot stop themselves from grabbing a bite every hour, though, so they need to do exercise.
