Fat burning

The human body is very efficient, and uses fat as a source of energy of last resort. Fat stores have allowed humans to survive countless famines over the last 10,000 years. It has been an evolutionary advantage to be fat, and have a slow metabolism.
When you exercise, the first source of energy your body uses is the calories you have recently eaten. Once you have burnt off the 800 calories from your most recent meal, your body taps into sugar known as glycogen, stored in your muscles and liver. A marathon runner will eat lots of pasta the few days leading up to a race, to fill his muscles with glycogen. This allows the runner to be able to run a full race without stopping to eat. This glycogen is also what fuels you overnight so your blood sugar doesn’t drop from not eating for 12 hours.
ONLY after you have burnt your most recent meal, and exhausted most of your glycogen stores, are you out of fuel, and your body looks to burn itself as energy. Unfortunately, muscle tissue is more easily used as fuel, and if not careful, you will burn muscle preferentially over fat for energy. Fat takes more time to be processed as energy and requires lots more oxygen to burn as energy. Consider muscle tissue as dry kindling wood, and fat is wet wood, burning much slower, and needing to be fanned to provide oxygen to help combustion.
So….here’s how to burn fat.
You must exercise on an empty stomach. The longer you have fasted, the quicker you are out of fuel, and begin to tap into body tissue for energy. Don’t eat in the evening, and exercise in the morning, this will be the longest time you will go without food. Limit carbohydrates in your diet. The less carbs you eat, the less “full” of glycogen your muscles will be, and the quicker they will be empty. Most importantly, is oxygen, if you don’t have enough, like wet kindling, you won’t be able to burn the fat. This means exercising at a much slower heart rate. You may do cardio at 160, but 120 is a much more appropriate heart rate for fat burning. It will seem slow at first, but you will learn the pace of exercise that maintains a slower heart rate. A good rule of thumb is, if someone were to call you during your workout, and you could have a 2 minute conversation without them noticing you were winded, you are in the zone. If you can’t carry on a conversation without talking funny, then you are in oxygen debt and don’t have enough oxygen to burn fat.
Caffeine can help, it speeds your metabolism, encourages fat burning, and will allow you to exercise just a little longer than without. In a study on caffeine, elite athletes were told to exercise to exhaustion. Half were given caffeine, the others were not. The group that took caffeine before exercise, exercised significantly longer than those that did not.
Lastly, if given the option of exercising 20 minutes every day, or 40 minutes every other day, you should choose the latter. It may take you 10 minutes at the start of a workout before you start burning fat, that means 10 minutes of fat burning in a 20 minute workout, but 30 minutes in a 40 minute workout. Remember this, as you reach the end of your workout and you’re getting tired. Every minute at the end of the workout is pure fat burning gold, push yourself, and stay on just a bit longer.
If you want to do weights and fat burning in the same workout, in a non fasting situation, do the weights first. You will need the quick energy of glycogen to have the strength to lift heavier. Also by doing weights first, you will use up your glycogen, and be ready to burn fat sooner during your fat burning at the end of the workout.