There is a whole industry built on this notion. Think about the countless types of cardio machines (with the famous „fat burning zone”), heart rate monitors, the number of fat burning magical workout programs, fat burning foods and, of course, fat burning supplements. There is money in it and these companies are making huge sums on your fat burning desires.
After a number of natural bodybuilding competitions (strictly drug tested competitions), where I went down to as low as 3% body fat, and training clients for years, I can say I have a very good insight and experience on what burns fat.
The term fat burning refers to the ability to oxidize (or burn) fat and use fat as a fuel instead of carbohydrates. “Burning” of fat is also known as beta-oxidation. Tissues can break down fatty acids by way of this beta-oxidation. The process of beta-oxidation ultimately produces ATP, which is the energy source for cells. This process is relatively slow and happens all day, every day, even when you rest.
Fat cells are a major storage site for body fat, and are in a continuous state of turnover. Fat metabolism is regulated independently by nutritional, metabolic, and hormonal factors; the net effect determines levels of circulating fatty acids and the extent of body fat.
It is becoming increasingly clear that the ability to oxidize fat is important for both performance and health. It is also well established that well-trained endurance athletes have an increased capacity to oxidize fatty acids. This enables them to use fat as a fuel when carbohydrate stores become limited. In contrast, patients with obesity, insulin resistance and type II diabetes may have an impaired capacity to oxidize fat. As a result, fatty acids may be stored in the muscle and in other tissues. This accumulation of lipid in the muscle and its metabolites may interfere with the regulation of metabolism.
Although evidence for this is not available it is appealing to think that an increased capacity to oxidize fat may aid those who want to lose weight and, in particular, body fat if used in combination with a negative energy balance.
There are a couple of factors that affect fat oxidation.
First let’s talk about exercise.
Yes, exercise burns energy. A number of studies showed that carbohydrate oxidation will increase proportionally with exercise intensity and that the rate of fat oxidation will initially increase but will decrease again at higher exercise intensities
Thus, while it is often claimed that you have to exercise at low intensities to oxidize fat, this is not necessarily true.
You might use proportionally more fat at low intensity but the full energy consumption of the exercise will still be lower than high intensity.
Also, the amount of fat that is used could be slightly increased only when your glycogen stores (carb stores in your body) are very low or empty...which is almost impossible to achieve as even an average, untrained human being has enough glycogen for hours of training...so it is very unlikely, that you could empty your stores.
Weight training burns the least amount of calories but if you go to the gym to burn calories your fat loss goals’ fate is sealed anyway (a bit more on this later).
The other important factor is diet. A diet high in carbohydrate will suppress fat oxidation and a diet low in carbohydrate will result in high fat oxidation rates. This could also be a bit deceptive, as low carb diet tend to decrease exercise performance, so during your session you will burn less energy (as you cannot work as hard or as long)...if you really want to experiment with low carb/high carb diets, it is up to you. You will be closer to the solution but still not close enough (a bit more on this later)
This one is my favourite. There are many nutrition supplements on the market that claim to increase fat oxidation. These supplements include caffeine, carnitine, hydroxycitric acid (HCA), chromium, conjugated linoleic acid (CLA), guarana, citrus aurantium, Asian ginseng, cayenne pepper, coleus forskohlii, glucomannan, green tea, psyllium and pyruvate. With few exceptions, there is little or no evidence that these particular supplements actually increase fat oxidation during exercise. Don’t spend your money on these!
All of the above factors can only have an effect on your weight, if your diet is very precisely adjusted, you know exactly how many calories you need, and then every bit of extra burnt off calories (either it comes from exercise, low carb/high carb experiments (let’s just call this the quality of the food), or some very slight increase from supplements) can cause weight loss. This is almost exclusively happens with competitors, who have been watching every bit of their diet for years. If you are not in this group then go on to the last section.
Take home message:
When it comes to fat loss, weight loss or gain, the most important single factor is the amount of calories you consume and the amount of calories you burn off. This is fact.
There are factors that affects your calorie/energy consumption but still, to be able to lose weight, you must eat less than you need.
It is great, that you exercise, it has a huge list of benefits, but fat burning, calorie burning is not on the top of this list. Yes, you can burn off a couple of hundred calories but it is absolutely useless, as a weight loss factor, if you eat a couple of 1000 calories more than you need.
So, to be able to lose weight, you need to eat less, than you need (calorie deficit). When you are in a calorie deficit, your body needs the missing energy from somewhere in your system. That could be your muscles (very easy and practical option for your body to get energy from there) and could be from other sources, like your fat storages (not an easy option, as your body will hold on to these storages as long as possible, as it is reserved for special cases, like when the food is scarce).
Your main goal in the gym should be to send a signal to your body, that you want it to get the missing energy from your fat storages and not from your precious muscles. Solution? WEIGHT TRAINING!
When you use your muscles during a weight training session that sends a very strong signal to your system, that you are actually very much in need of those muscles and they shouldn’t be touched. Guess what, your body will turn to your fat reserves!
Your action plan is the following:
1. Control your diet!
If you want to be bigger, eat more, if you want to be smaller, eat less than you need. Without this, you WILL NOT see results!
2. Do weight training!
This will send a signal to your body that you need your muscles.
Do you weight training in a smart system to train you muscles often enough, but let them recover, as well.
3. Eat smart and have a good night sleep!
This is the time when your body burns the most fat. Your damaged muscles have to be repaired and an 7-8 hours sleep is the perfect time for your body to use the otherwise slow process of beta oxidation („fat burning”) for the required energy.
4. Next time, when you hear about a fat burning workout or fat burning supplement...smile! You already know „The Secret”
If you have any question, feel free to comment or message me.
Happy fat burning! :)
Precision Nutrition - All about fat loss
Sport Nutrition - From lab to kitchen by Asker A. J.