Hi all,

OK I want to lose weight.

At the moment I am doing interval training pretty much every morning. So walking, running, walking, running, sprinting, that kind of thing.

My question is how does the body burn fat?

I've head all sorts of stories how doing intensive training like interval training only burns muscles? You have to do small amounts of cardio for a long time to burn fat? Is this true?

Also does the body burn muscle first then fat?

Can someone draw me a fat burning program?

I have read his book, it is GOOD!
http://www.burnthefat.com/main.html

Bottom line there is not much credence to any of the "fat burning zones" Nor do MOST people have to worry about muscle being burned.

The body has 3 sources of fuel. Fat, glycogen (stored carbohydrate) and in a pinch protein (muscle).

While effort level will affect the PERCENTAGE of fuel source burned, in the long run it makes very little difference.

When you are at rest or at very low low low levels of activity your body burns a high % of fat for fuel (except your brain which really prefers carbs). So in theory you are in the "fat burning zone" right now sitting on your computer. Problem is you arent burning very many calories at all.

At extremely high intensities - all out maximum - you are burning almost exclusively carbohydrates for fuel. Glycogen is stored in the muscles. However, as soon as you stop exercising and eat, the body places a very high priority on reloading the muscles. So then you burn more fat just living because the body steals the carbs you eat to refill the muscles for next time.


The body only burns muscle for fuel (beyond normal waste recycling which is a different topic) under extreme duress. Despite what you will read in some muscle mags, the body does not burn muscle for fuel under extended cardio situations unless a few other situations are also triggered.

One is extremely low carbohydrate intake combined with high intensity workouts.

One is overtraining syndrome (which is more specific than merely "working out too much) where the body starts to lose its ability to repair and continued high intensity workouts can cause catabolism.


Short answer is just move, sometimes easy, sometimes hard and as long as you burn more than you eat you will lose fat.

Great post! It seems like lately everyone is into the "biggest loser" mode and doing so much high intensity exercise, but it's good to be reminded that low intensity is beneficial too. I like to do the interval walk/jog to get my heart rate up, but I also enjoy a good yoga or pilates workout. Variation prevents boredom and keeps our body guessing!

OK please excuse my ignornace when I ask further questions as I am still trying to get my head around this whole how is fat burned how is muscle burned.

Q1
If I do weights to the point it burns my arms so I am breaking muscle down. Will the body use fat to create muscle? I say this because people say "you can turn fat into muscle"

Q2
If I do interval training, so high cardio then low cardio, then high cardio on an EMPTY stomach. So first thing morning say. What will my body burn to get energy? Calories? (well how? if I haven't eaten anything?) Stored body fat? Or muscle?

Also what will my body burn first if I had say, a snack, food before training? I assume calories? So what will it burn when it has burned all the calories off?

Your questions are actually related:

Fat is energy and your body uses energy throughout the day. Your body uses protein to build muscle and some of the protein it can get that is stored in the body and other protein it gets from the food you eat.

Your body does have a variety of energy sources, it has glycogen which is its preferred energy and it is the energy stored in your muscles. It also has fat and lastly it has muscle. If you are burning calories, then your body chooses one of its energy sources to get those calories. Short term exercise tends to burn mostly glycogen. Your glycogen stores are filled up when you eat. It well then break down fat and if you go on long enough, it will burn a mixture of muscle and fat.

Really, I wouldn't worry overall. The only time you should worry about eating before a workout is if you find yourself weak for the workout and need food to fuel the workout. Also if you are doing a long, intense workout such as running for well over an hour, then you might also want something mid workout.

If you do not have enough protein to make muscle will the body use fat to create muscle?

Fat is fat and is energy. Your body will either create amino acids or it will take them from the food you eat. You should also understand that muscle is created within a couple days of you breaking down your muscles. So as you are doing a squat, your body isn't building muscle that second but any muscle fibers that are torn will be recreated over the next day or two. The act of creating muscle takes energy though as well as just being alive takes energy.

Fat and muscle are two completely different entities. You can lose fat, but it doesn't "turn into" muscle. Fat cells can increase and decrease, but it doesn't turn into something else i.e. muscle.

See these posts confuses me. If fat is energy? Doesn't it get used up as fuel? so is essentially being used up?

What confuses me is doing cardio burns calories, doing weights burns muscles and is replaced by protein. So what burns fat? Or how is fat used up? I understand that fat is used up when in a low low activiey state like another poster said but how is it being used up while active?

No.

Doing weights does not burn muscle. That is incorrect. Cardio burns calories. Doing weight-training burns calories. Doing weights also encourages the body to store SOME calories as muscle.

Fat is calories. Carbs are calories. Protein is calories.

Your body can pick ANY of these to use for fuel (energy).

Your body prefers to use carbs or fat for fuel and usually burns a mixture.

Excess calories ingested of ANY variety will be broken down( digested) and stored as fat.

For your purposes ANY situation where you ingest FEWER calories than you burn will result in fat being used to make up the difference = fat loss.

It does not matter if you burn these calories slow or fast. If you burn more calories than you eat you will lose fat.

It does not particularly matter if you exercise on an empty stomach or not. All that matters is total calories burned throughout the day vs. total calories consumed throughout the day. Timing doesnt matter. The body will burn stored carbohydrates and fats as it needs them.

The body will not under most circumstances burn muscle.

Fat is potential energy. It is there, waiting to be used. Your body has put it there JUST SO you will use it when you need it. By exercising more and eating less than you need for that movement, you're body will turn to the fat to keep you going. Think of it as back-up fuel. It is used up no matter what activity you do.

How fast it gets used up depends on the kinds of activity you do--and how much of a calorie deficit you run. But there is a limit. If you try to create too much of a calorie deficit your body won't let go of the fat (why should it: it thinks there's probably another famine on the way!)

right.

oops, let's get this straight. Weight training does NOT "burn" muscle. It tears the micro-fibres in your muscles. The body then uses the protein you eat to repair and rebuild your muscles. (That's why you should always have a day of rest between weight training sessions: to give you body a chance to heal)

Weight training does contribute to weight loss, though, because all this rebuilding and repairing takes energy--and, again, as long as you are eating less than you need to move, then your body has no choice but to take this energy from your fat. You will NOT lose weight by doing weights without a calorie deficit, though.

Did I answer that above for you?

Keep asking questions! I know I am a perfect stranger, but I have an overweight son who, I hope, will do something about it--just like you are! So, I'm proud of you.

Ah I see. Thank you ennay and Alana in Canada for breaking it down to simple terms for me.

So essentially for weight loss you have to burn off the calories you ingest. The few calories intake and the more you burn = higher chance the body will take fat and use/burn it as fuel.

So if you stay active throughout the day, walking up the stairs, walking, just basically moving your body as much as you can, you will burn the calories off and when that is used up the body will burn stored fat?

Yes basically. Your body will burn what you eat as well as what is stored. Lifting weights also requires energy which is why it burns calories as well and the more muscle you have, the more calories you burn just by being alive which is why building muscle is important.

Ah that's good then. You can tell I failed Biology can't you?

So tell me something about starvation.

If I starve my body is that bad? This assume will made my body store fat rather then using it right?

What happens if I starve myself but still do exercise? Will I still burn calories/fat?

Edit: Also why is water important in weight loss? On a normal day I estimate I drink 1.5 litres which isn't anything near the recommendation as people say. Does it have to be water or is fruit juice fine?