Why Cardio Doesn't Work for Fat Loss
There are still some people who believe that a steady state cardio type of exercise is the best choice for body fat loss. This is wrong, sports science has proven that banging away on an elliptical or treadmill or some other sub-max cardio machine is suboptimal for losing fat.
The logic of cardio not working for fat-loss comes from that infamous "fat burning zone" made popular in the 1980's when aerobics was put on the map for the first time. Humans have an almost completely unlimited supply of fat. A 200lb man with a body-fat of only 10% has about 15 billion fat cells he can burn when he runs out of muscle glycogen.
Those 15 billion cells will contain about 67,000 calories, which is plenty to give you 2,000 calories a day for over a month. That means you could go for 30 days without food and still have a heart-beat. The bad news is that you'll have enough intra-muscular fat stores and circulating free-fatty-acids stored in your blood, muscle and your liver glycogen.
Your circulating blood glucose will be used to fuel most of your daily activities, including your training. Your stored adipose fat is just like the U.S. oil reserves. They only used under extreme conditions. When your fat is moved to its long-term storage facility, it becomes part of your last resort.
For your body to start relying solely on your own "stored oil reserves" i.e. adipose fat, it needs to become a major adjustment to your daily nutrition and your exercise you do. When you select a steady state cardio exercise to lose fat you'll be losing a lot of potential benefit that you could get because your body is able to spare calories burnt when in this slightly elevated state.
In order to maximally burn your stored body fat using exercise you need to consider two important issues: high-effort, energy depleting exercise together with muscle-preserving type resistance training. The rationale is something you should be familiar with.
Training with greater intensity will mean using a lot more muscle to deplete those immediate energy stores coming from your blood glucose, your stored glycogen, your intramuscular fat, and your free fatty acids. When training with a high-intensity workload, it means your body needs to obtain its energy from other sources. This forces your body to go after adipose fat in two different ways.
The first is post-workout, whenever your body gets depleted of its immediate energy sources, you then require your stored fat to help in the recovery process. This relies on your post-workout nutrition if it is addressed properly, similar to digging a hole, then refilling it.
Your workout is when you are digging the hole. The more demanding your workout is, the deeper you're digging the hole. Your recovery nutrition is then your filler. If you're able to slightly under-fill this hole you dug, still providing proper nutrients, you're then able to use more recovery energy leading to more fat being pulled from your stored adipose fat.
You also don't want your body use its metabolically active muscle-tissue. This is why any highly intense resistance training is so critical for any decent fat-loss program. Any resistance training done either preserves muscle or builds muscle. When you stimulate muscle tissue using hard resistance training the body will then be forced to use stored adipose fat to recover lost energy in order to maintain and grow muscle.
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