Andrew Pohlman wrote: ↑
Fri Sep 22, 2017 5:26 pm
Another common misconception is that you can exercise away excess calories. Not really, no. Not for people with desk jobs like me! For example, the professional cyclists in the Tour de France burn approximately 5000 Kcals per day. They eat like crazy during such events and never gain an ounce due to many hours of high intensity physical output. But normal people? We burn less than 2000 Kcals/day. To burn just one 300 Kcal doughnut takes an hour of moderate cycling. So fine - eat that doughnut, and compensate by an hour of cycling. But then what? If you want to have a net loss of fat, you have to manage calories as outlined above.
I'm sure you don't mean to put people off exercise here. Of course you can't compare somebody with a desk job to an elite athlete, but you don't need to. If you are in shape and weigh say 80 kg (180 lbs) you can easily burn 800 calories in a 1.5 hour workout. It is only the equivalent of running 10k in 1.5 hours, which is a slow jog. Anyone can get in that kind of shape. The bike is a terrible choice if you want to burn calories, and running is not much better - you will get through a lot more if you opt for the cross trainer or rower.
If you do any meaningful exercise your body will need to recover and regenerate, and that process takes energy and therefore burns calories. On the other hand, you may eat more after working out or feel you've earned a treat. Sweet and fatty foods are so high in calories that you can always wipe out the benefits, but you can definitely make a huge change in your body shape by exercising.
First off, nobody really wants to lose "weight". People really want to lose fat. Limiting total calories, particularly carbs, is essential to triggering the burning of fat. The body prefers to burn carbs (glucose), then protein, then fats, in that order. The carbs come from two sources: the digestive system, and conversion of stored glycogen to glucose. So the game is to set up physiological conditions so your body burns fat despite its normal propensity.
I don't believe it matters what order the body burns calories in, only whether it burns fat at some point. If you have more calories going out than coming in, it has to burn fat at some point. It doesn't matter when.
You will see fat burning modes on CV machines in the gym - these encourage overweight people to choose low intensity exercise in the belief that it will help them lose weight. It doesn't. It is true that the energy you use *while exercising* will come more from fat and less from carbs if it is low intensity exercise, but that doesn't matter. You will burn more fat overall if you burn more calories overall, which means you should not be keeping the exercise intensity artificially low. It seems to me that these fat burning modes are just a case of marketing people preying on the overweight.
There are whole books written on this stuff. It's very hard to give a concise synopsis here. It gets very complicated and to my chagrin, most healthcare professionals in the US don't know even basic nutrition, so they are of no help for people in need of weight management.
Well, I am not sure how much difference it really makes. If someone is overweight it's usually because they eat for reasons that have nothing to do with being hungry - out of boredom, say, or as a way of cheering themselves up. Time and time again people make huge efforts to lose weight only to rebound. I think this is because their basic attitude to food does not change, and no amount of nutritional information is going to help there. On the other hand, when people who had been put off exercise for whatever reason rediscover what a pleasure it is, it can become an integral part of their lifestyle. I think that's the way to sustainable weight loss.