T Nation

Burning Fat or Protein for Fuel?

So… on a restricted carb diet how can you tell what your body prefers to burn for fuel?

If by the end of your “cut” you look like Christian Bale in the “The Machinist”, you’ll most likely be able to conclude it was using protein.

Seriously though, by controlling your protein intake. Too high and your body will adjust to protein as its main fuel source. If you have around 1.0 - 1.5grms per pound of body weight and make up the rest with fats, you can safely assume that your body is in fat burning mode.

Just make sure your calories aren’t drastically cut, then muscle wasting is going to happen either way.

It depends if you’re fat adapted.

Glucogenesis (where your body turns protein into sugar to run on) makes you feel tired, sluggish, and slow.

Inefficiently running on fat feels the same way, but it stops feeling that way after a few days (adaptation).

OK my bodyweight right now is 216 and my bf% is 25-27. I’m taking in 1800-1900kcal daily but only doing weight training and moderate (130-150bpm) cardio for 30 minutes a day, 6 days a week. The breakdown is 252g protein (slightly over 1g/lbs) and 90g of fat (of course from good sources.)

And from what I gather from you all it sounds like I’m in the clear. And god no, I would rather be a fat ass than look anything like Christian Bale.

Thanks.

How long have you been aiming for fat loss? I ask because if you just started, I’m not sure if I would start out with that low of calories.

[quote]cman10 wrote:
How long have you been aiming for fat loss? I ask because if you just started, I’m not sure if I would start out with that low of calories.[/quote]

Well, as of today, 4 months. I tried maintenance level and had good results with my increased activity including some HIIT and strength training. Before even starting I was eating about 3000+ calories and weighed 235-240, bf% of 34 (self calculated through measurements.)

The dropping of junk food plus the activeness burned about 20 pounds in 3 months while strength increased and measurements decreased. But for 4 weeks I haven’t shed a pound and Starting Strength has served it’s purpose. I could stick with SS routines but I fear adaptation, and to stay motivated I have to change it up because I get bored easy. I still perform the compounds just not 3 times a week.

I know what to look for as far as fat loss goes but with measurement-only bf% calculation the lines are blurred a bit when it comes to telling if you’ve lost the mass of muscle or fat (and on me fat is stored everywhere, so every measure could be affected.) And that’s why I asked my original question.

[quote]meanest wrote:
OK my bodyweight right now is 216 and my bf% is 25-27. I’m taking in 1800-1900kcal daily but only doing weight training and moderate (130-150bpm) cardio for 30 minutes a day, 6 days a week. The breakdown is 252g protein (slightly over 1g/lbs) and 90g of fat (of course from good sources.)

And from what I gather from you all it sounds like I’m in the clear. And god no, I would rather be a fat ass than look anything like Christian Bale.

Thanks.[/quote]

Christian Bale is awesome. Even when he looked like a psychotic stick :slight_smile:

Honestly… I would say your protein is a bit high. I’d drop it closer to 200 and cut in some extra fat. I had a similar thing happen on my current diet- I was taking in 250g protein out of 2500 total calories, and started getting drowsy and foggy in the midafternoon for no reason. Dropped my protein, replaced with fat, and BAM! glucogenesis gone.

Also, do you have planned carb loads (or whatever you want to call it)?

[quote]meanest wrote:

Well, as of today, 4 months. I tried maintenance level and had good results with my increased activity including some HIIT and strength training. Before even starting I was eating about 3000+ calories and weighed 235-240, bf% of 34 (self calculated through measurements.) The dropping of junk food plus the activeness burned about 20 pounds in 3 months while strength increased and measurements decreased. But for 4 weeks I haven’t shed a pound and Starting Strength has served it’s purpose. I could stick with SS routines but I fear adaptation, and to stay motivated I have to change it up because I get bored easy. I still perform the compounds just not 3 times a week.

I know what to look for as far as fat loss goes but with measurement-only bf% calculation the lines are blurred a bit when it comes to telling if you’ve lost the mass of muscle or fat (and on me fat is stored everywhere, so every measure could be affected.) And that’s why I asked my original question.[/quote]

Congrats on the progress so far. I went through my last fat loss cycle about 6 months ago, and made the mistake of eating up too much muscle instead of fat, so it is good to see you making sure your not doing the same. I would follow Otep on the increasing fat while decreasing protein, as well as making sure your carb up day is planned as well.

I was instructed to take in my carbs in my post-workout meal if I have any carbs at all. No mention of a carb-up day. I’ll find out on Monday though as I phone in my PT friend who advised the program in the first place.

Carb-up days refill glycogen in muscle tissue. The idea is that, as you go for longer periods without carbs, your body becomes more sensitive to them, so when you finally DO get them, it shoves them where you want to put them- the muscle tissue.

Carb loads are often not advised for really fat dudes because your insulin sensitivity sucks so badly even after not getting carbs for days on end your insulin STILL shoves the energy into adipose tissue (because there’s so much of it).

If you take in carbs after a workout, there is often not a need for a weekly carb-up (because your glycogen levels never drop low enough).

When you talk to your PT, ask her about your body catabolizing muscle tissue. Most of your nutrition seems on point, so she’d probably have good input on this too.