Max burn per day?

Expatmommy79

I'm on a mommy forum and someone said that there was a maximum amount of fat calories that can be burned per day and that's why too much exercise is bad while in a deficit... At some point the burn slows/stops.

It makes no logical sense for me and can't find a study or reference to support it.

Anyone know what this might be referring to?

TeaBea

Expatmommy79 wrote: »

I'm on a mommy forum and someone said that there was a maximum amount of fat calories that can be burned per day and that's why too much exercise is bad while in a deficit... At some point the burn slows/stops.

It makes no logical sense for me and can't find a study or reference to support it.

Anyone know what this might be referring to?

I don't know what study you're referring to. But keep in mind exercise and eating less isn't just about "burning fat." Your body will also burn existing lean muscle.

Weight loss will be fat, muscle, and water loss. Many people try to limit muscle loss with a moderate weekly weight loss goal, getting enough protein, and strength training.

jemhh

There was one study that posited that 31 calories per pound of body fat can be used from your fat stores each day, meaning that your lbs of body fat multiplied by 31 would be the maximum deficit you could have without sacrificing lean body mass. Here's a discussion on it from Lyle McDonald's forums and here's the link to the study.

Correction: the link above is the summary of the study. This is the study (you may need to be on a network with an Elsevier subscription to access it.)

brb_2013

I recall reading on another forum that the body can only release a certain amount of calories out of its storage per day. Now I don't remember the details but it did seem to make sense, and it was this person's justification for why one should not drop a deficit too low- the body just couldn't give up an extra whatever once it used a certain amount. So if it were true, the idea is if you eat 1500 and exercise 500, but your body needs (estimate) 2000 calories to maintain then your body is supplying the deficit from fat stores. The deficit here is 1000, within what the body can supply. Dip too far, say with a 1500 calorie deficit, and your body can't keep up releasing fat that quickly. I believe the person claimed for his body it was about 1800, a deficit bigger than this and he would stall. Reducing the deficit gave him the edge to continue losing.



I don't think I ever gave it another thought until now, if I'd seen proof it would make sense to me. It doesn't seem so far beyond reality that it is woo.

Jruzer

Right. It' snot that too much exercise is "bad", but that too big of a deficit is bad.

MikeInAZ

I did the Spartan Race 3 weeks ago. Then volunteered there for 9 more hours. The last 2 hours we had to dismantle and clean up. Basically it was another workout. According to my Polar M400 I burned 4800 calories that day, being active for 12 hours!

I'd say, that was enough!

MikeInAZ

I think your typical combat Marine will burn over 5000 calories a day. Carrying 80lbs of gear in 100+ degree weather for 10 or 12 hours will burn a lot of calories and fat.

cwolfman13

Expatmommy79 wrote: »

I'm on a mommy forum and someone said that there was a maximum amount of fat calories that can be burned per day and that's why too much exercise is bad while in a deficit... At some point the burn slows/stops.

It makes no logical sense for me and can't find a study or reference to support it.

Anyone know what this might be referring to?

I don't know what the figure is, but yes...there is only a certain amount of fat that can be oxidized in a 24 hour period. The only way this would relate to exercise is if someone were eating a substantial deficit and then doing a bunch of exercise on top of that creating an even greater deficit. Huge deficits consume lean mass.

Too much exercise in a deficit is relative...you can do a *kitten* ton of exercise and still feed that fitness and still be in a deficit. When I was training for my first endurance ride and still tracking I was eating around 3,000 calories per day and losing about 1 Lb per week...I was still in a deficit, but I was still also adequately fueled. Now, had I been doing that training and eating 2,000 calories or less...yeah...that would have been a disaster.