Can you "starve" to force body to convert body fat to energy (25%+ of body fat)?

[torentas]

My brother is having 25%+ fat in his body. If his daily calories dosage is 2500 cal aside of weight lifting, can he eat less (like 2000 cal) a day to force his body to convert the excess fat to energy?

Basically, I am sure that this would not happen if you have 18% or less of fat. But I am not sure what is going on in case of so much extra fat.

And I am also not sure if body would reject to convert this fat to energy but rather muscles would not grow.

[gbullock32]

Seriously, are you asking if eating less than you need will cause the body to turn to stored fat as an energy source?



Yes it will, no matter what your body fat percent; eat less than you need and you will use fat to make up the difference.

I cannot believe this is an actual question.

If overweight or new to lifting it is likely you will gain muscle even in a calorie deficit assuming proper training.

[AdamWW]

Please tell me you're not actually 42

[torentas]

I was not sure. Better to ask .

So basically, the body will convert fat to energy to a point when there is no more fat, right? Then it starts atrophying muscles to convert to energy.

[torentas]

Please tell me you're not actually 42

Wouldn't you like to know

[gbullock32]

I was not sure. Better to ask .

So basically, the body will convert fat to energy to a point when there is no more fat, right? Then it starts atrophying muscles to convert to energy.

Yes, unless you do not weight train, them more of each pound lost will be muscle as the body will not prioritize muscle retention.

And if you hit the point of muscle depredation, you should definitely stop losing weight as you would be very lean.

[Mrpb]

My brother is having 25%+ fat in his body. If his daily calories dosage is 2500 cal aside of weight lifting, can he eat less (like 2000 cal) a day to force his body to convert the excess fat to energy?

Basically, I am sure that this would not happen if you have 18% or less of fat. But I am not sure what is going on in case of so much extra fat.

And I am also not sure if body would reject to convert this fat to energy but rather muscles would not grow.

He needs to lift on a good program and eat moderate energy deficit every day. He will lose fat and build muscle, assuming he's a beginner.

The more advanced he becomes, the harder it will get to build muscle in energy deficit.

[boo99]

I was not sure. Better to ask .

So basically, the body will convert fat to energy to a point when there is no more fat, right? Then it starts atrophying muscles to convert to energy.

How low are you planning to go?

Those extreme situations, especially atrophy, are conditions that you don't want to be near, ever

[cljolley]

This is hilarious. I’m sorry. The whole reason your body stores fat is so that it can be used at a later time. If in fact you were starving, your body will deplete it’s fat stores (and muscle) to fuel itself. Have you ever seen somebody that starved to death that was fat?

Anyways in a realistic scenario there is a huge difference between starving yourself and eating at an acceptable deficit. If you try to starve your body you can bet you’re gonna drop weight FAST, but you’re also going to run into a few small problems like...oh idk... multiple organ failure, tremors, parts of the brain shutting down.

[SuffolkPunch]

OP, you are right in principle - but you cannot simply starve because things aren't that simple.

Your fat stores can only supply a certain amount of energy per day - and you also need amino acids and other essential nutrients otherwise your health will deteriorate and you will lose muscle - and that will happen even when you still have plenty of fat remaining.

Practical advice: don't attempt to lose more than 1% of your bodyweight per week.

[SuperHippo]

OP, you are right in principle - but you cannot simply starve because things aren't that simple.

Your fat stores can only supply a certain amount of energy per day - and you also need amino acids and other essential nutrients otherwise your health will deteriorate and you will lose muscle - and that will happen even when you still have plenty of fat remaining.

Practical advice: don't attempt to lose more than 1% of your bodyweight per week.

If I remember correctly a study showed the fat can liberate about 31 calories per pound of fat per day.

[MasAyinde]

Typically your body will choose to use simple carbohydrates and protein in muscles for energy, unless it determines that there is a need to keep muscles (by weight training). If you are in serious caloric deficit without accompanied resistance training, you will likely get flabby as your body uses muscle for energy, which is easier to break down and convert than fat.

[Mrpb]

Typically your body will choose to use simple carbohydrates and protein in muscles for energy, unless it determines that there is a need to keep muscles (by weight training). If you are in serious caloric deficit without accompanied resistance training, you will likely get flabby as your body uses muscle for energy, which is easier to break down and convert than fat.

This is not the way it works. My suggestion is to stay around here and do more reading. Start by reading the stickies. My signature contains a couple of good websites.

[Heisman2]

If I remember correctly a study showed the fat can liberate about 31 calories per pound of fat per day.

That seems to come from this study which I have not yet read but will do so today most likely: https://www.ncbi.nlm.nih.gov/pubmed/15615615

[Heisman2]

Alright, read through it (well, skimmed at least; would take me hours to go through the math well). He uses data from the Minnesota Starvation Experiment to generate that number. It is important to realize they were not doing resistance exercise, they were not doing a high protein diet, and they on average were fairly lean initially (starting at ~10 kg of fat). Additionally, the FFM component is not divided in any way (ie, it includes muscle, glycogen, organs, etc).

If that number applies to all situations though, then as an example for someone who weighs 180 at 15% bodyfat, and thus with 27 pounds of fat, they could lose 837 kcal from fat/day, for a weekly deficit of ~5800 kcal and roughly 1.6 pounds of fat lost per week. A little less than the commonly cited 1% weight loss per week goal that many (myself included) throw out. I think that's ok though as I believe a high protein diet and resistance training will help spare skeletal muscle.

[Mrpb]

The Garthe weight loss study in athletes compared a group on a ~500 kcal deficit with a group on a ~800 kcal deficit, both groups doing resistance training. There was no difference (!) in fat loss per week. The smaller deficit group managed to gain some LBM, the larger deficit group didn't.

[AdamWW]

The Garthe weight loss study in athletes compared a group on a ~500 kcal deficit with a group on a ~800 kcal deficit, both groups doing resistance training. There was no difference (!) in fat loss per week. The smaller deficit group managed to gain some LBM, the larger deficit group didn't.

I wonder if that relates to adjustments in NEAT and overall movement and energy-burning tendencies outside of training...

Also curious about the macro breakdown during restriction.

[Mrpb]

I wonder if that relates to adjustments in NEAT and overall movement and energy-burning tendencies outside of training...

I don't think that caused the difference. I think the difference was caused by the SR group gaining LBM.

Shame that protein intake was on the low side.
https://www.researchgate.net/publica...Elite_Athletes