As a lot of people want to burn fat, many of the weight loss myths and misconceptions you get are in this area. Wellness experts Tony Ryan and Martica Heaner, authors of Cross-Training For Dummies, note, ‘Your body burns either fat or carbs depending on the intensity of your activity. But when it comes to losing weight, calories are calories. You burn fat even when you’re in couch-potato mode. Yet, a lot of misunderstanding prevails.’ So let’s break down some of the myths you have about burning fat.
1. Your Body Completely Shuts Off One Fuel Source When it Turns On Another: According to Ryan and Heaner, ‘What has often been misunderstood by both exercisers and exercise instructors alike is that the body relies on both fat and carbs for energy all the time, albeit in different ratios. In fact, as you sit here reading, you may be burning about 50-60% fat and 50-40% carbohydrates. You’re not using much of either, however, because the amount of calories you need probably amounts to about one or two calories a minute. If you were to get up and start jogging in place, your body would need to supply you with some quick energy to do so, so the metabolism ratio might shift to drawing upon more carbohydrates, say 70%, and less fat, say 30%.’
Ryan and Heaner go on, ‘If you were to continue jogging, then, in order to preserve the carbs (which can run out since you have limited stores in the body), your body would gradually shift its metabolism ratio again to say, 60% fat and 40% carbohydrates. From an energy efficiency point of view, it pays to be fit. The endurance athlete would be able to make the shift sooner, and his fat-burning percentage might be 65-75%. However, in practical terms this is purely technotalk, and these ratios don’t make a big difference when it comes to losing weight and decreasing your body fat. For the most part, athletes are often leaner not because they might rely on slightly more fat for fuel, but because they practice their sport two to three, or more, hours a day — this burns a lot of calories.’
2. Low Intensity Exercise Burns More Fat: ‘In a strict scientific sense, these claims are true because working at a lower intensity requires less quick energy and a higher percentage of fat is burned,’ Ryan and Heaner admit. ‘But you’ll also burn fewer calories than you would if, for the same amount of time, you work out at a harder intensity (running versus walking). If you’re trying to lose weight, even though a higher percentage of fat is being used, a lower total amount of fat is lost. Whether increased fat burning will result in actual weight loss is dependent upon several variables, including the total calories burned (which include both fat and carbohydrate calories) and the total fat calories burned. If you do work at a low intensity, you need to increase the time spent exercising to burn more calories. What matters most is the total number of calories burned. If you burned 250 calories every day from a short, fast jog, you’d see a bigger difference in weight and fat loss than if you walked every day for the same amount of time.’
3. Cardio Activities are More Fat Burning after 15 or 20 Minutes: Ryan and Heaner note, ‘Technically, once you’ve been exercising for 15 or 20 minutes, your body has made the shift to using a higher percentage of fat for fuel. But again, if you’re trying to lose weight, it’s about the total number of calories burned, not necessarily the fuel source. For example, say that at rest you burn up to 60% fat. When you enter the initial phases of intense exercise, the ratio changes. You may now burn only 30% fat because your body is using quick-energy carbohydrates. Once the exercise is sustained, the body switches back to using a higher percentage of fat to fuel the movement (up to 75% fat). In this aerobic phase of exercise, a higher percentage of fat is being used for energy. But if you aren’t working out for a very long period, you may still burn more total calories and, therefore, more fat calories working out harder.’