Is there a difference?

mpawlicki

Between sitting on your butt all day long and eating at a 500 calorie deficit vs. walking 20000 steps/day and eating at a 500 calorie deficit?
Other than being able to enjoy food vs. starving yourself? Does fat burn off faster in the second scenario?

xcalygrl

Deficit for weight loss.
Exercise for health. Your cardiovascular system (lungs, heart), joints, and muscles could possibly be healthier in the 20,000 steps/day scenario.

heybales

The second scenario tells your body you want to use at least the leg muscles, so even in the face of a reasonable deficit, you can retain some muscle mass.
Sadly if you have muscle upstairs that is not being used in either scenario, likely to slowly go away.

Now, that depends on if the 500 cal deficit is with a lot to lose, or little to lose.

But as far as more fat loss, no.

Actually, compared to sitting when probably 95% of your energy use is supplied by fat, and walking where maybe 60-75% of it is fat, (but more grams burned because more calories burned overall), the fat burn from the exercise comes in to play later.
Because during the walk you used more carbs from the liver and the muscles than you would resting.

So now your next meal, all available carbs goes to fill those stores first (and in a diet muscle glycogen stores are always lower than possible), and any immediate energy needs.
Once that is accomplished, faster than if it didn't need to be done, insulin drops, fat release and burning returns back to normal.

But it returns faster than it would have normally. That's actually where the fat burn from a diet occurs - not during the workout.

Fun with numbers.
If you did an intense workout burning 800 calories an hour, and that's intense enough say 80% carb burn, 20% fat.
800 x 0.2 = 160 calories fat / 9 = 17.8 grams of fat burned (9 cal per gram) in that hour.
800 x 0.8 = 640 calories carb / 4 = 160 grams of carbs burned in that hour.

Your next meal of say 400 calories is 40% carbs - or 160 calories or 40 grams.

Your insulin goes up because you ate, fat release from cells is turned off, and insulin sends carbs off to storage in liver and muscles. Fat eaten is used for energy, and protein sent off to wherever body needs it.
Since your meal doesn't even make up for what your workout burned in carbs, doesn't take long to digest and process that food, blood sugar drops, insulin is dropped or muted with glucagon release, and fat release from cells is back.
Much faster than otherwise, 2-4 hrs perhaps.

If eating at maintenance, not as much storage to top off, so body uses some of what it ate as immediate energy needs, can take 4-5 hrs for that.

So the exercise gave you 18 grams of fat burn, which isn't over what you would have burned, it includes it actually.
But the getting out of elevated insulin state back to normal has helped burn more fat later - if you are in a diet with slightly lowered carb stores anyway.

And this is why the idea of eating every 2 -3 hrs, while it really won't change the calories in / out rules, does leave you with elevated insulin and fat cell burning turned off that whole time you are doing it, waiting until the night when you finally stopped eating.