In my previous post, I discussed the common belief that decreasing your caloric intake and increasing your activity level is all you need to lose fat and improve your fitness. I explained why exercise, not just increasing your activity level, is essential for long-term fat loss and fitness. In this follow-up post, I will focus on caloric intake part of the belief and explain why decreasing your caloric intake is not always good for fat loss or overall health and fitness.
First, I want to acknowledge that it is certainly true that you must burn more calories than you consume if you want to lose weight or fat. Unfortunately, people often take that to mean the fewer calories you eat, the more fat you will lose, which is simply not true. It is much better to exercise and decrease you calories by a reasonable amount, such as 300-500 calories a day, than it is to cut your calories drastically. Even if you are exercising, a drastic calorie reduction, such as eating fewer than 1000 calories a day, will end up hurting you in the long run.
Decreasing your caloric intake will improve fat loss, but only up to a point. You still need to consume enough calories and nutrients to give your body what it needs to function properly throughout the day. Calories are used as energy/fuel, not only for your muscles, but also for your brain and every other part of your body. If you don’t consume enough calories and give your body the energy it needs, your body will fight back and try to conserve as much energy as possible.
It would be nice to think that severe caloric restriction would force your body use your fat reserves for energy, but unfortunately the opposite actually occurs. During times when your body is not getting enough calories or nutrients, it essentially goes into a conservation or starvation mode. When this happens, your body actively works to conserve fat, instead of burning it.
During this time, your metabolism will slow down, so your body will not need to burn as many calories during the day and less fat will need to be converted into energy. In addition, your body will start breaking down greater amounts of muscle to be burned for energy/fuel, again so fat can be spared. The unfortunate truth is your body considers fat to be more valuable that muscle, because fat is a more concentrated source of energy, which is necessary from a survival standpoint.
Of course, even with your body doing everything it can to conserve fat, some fat loss will still occur, especially at first. It is common for people to have initial success with a low caloric intake, but soon they stop losing weight. Some people then try to eat even less, thinking that will stimulate further fat loss, but it actually makes the body more resistant to losing fat and more likely to lose muscle. This in turn will have a negative impact on your level of fitness and your metabolism, both of which will make it more difficult to lose fat or prevent fat gain in the future.
People commonly try to combat these problems by exercising more, because exercise can increase your metabolism and help conserve muscle during dieting (if the correct types of workouts are performed). While exercise appears to be a good solution, the results are often mixed at best. The problem is that the body already does not have enough energy (calories) to carry out everyday physiological functions, so exercise acts as an added energy drain on an already struggling system.
If your body does not have enough energy just to get you through the day, there is no way your body can adequately recover from working out. Exercise may result in some more initial improvements in fat loss, but eventually your body will start getting run down and you will not be able to keep up your exercise routine. Not only will you feel worse, you will put a strain on your immune system and increase your chances of getting sick. Ultimately, you will either have to stop exercising, start eating more, or both.
Another big problem with severe caloric restriction is what happens after a return to normal eating habits. These very low-calorie diets cannot last indefinitely and once caloric intake increases, your body will actually start trying to hoard as many calories as possible. This is a direct response to not getting enough calories in the past and it is the body’s way of preparing for future periods of caloric restriction. In other words, your body will store even more calories as fat from your meals than it normally would.
As a result, it becomes easy to gain back the recently lost weight and many people actually regain a higher percentage of fat than they lost on the diet. After regaining a significant amount of weight, the person may try to lose the weight by going back to the previous extremely low-calorie diet, thus starting the cycle all over again. This is essentially what happens with yo-yo dieting and it never a good plan for trying to achieve long-term weight or fat loss.
To avoid these problems and achieve positive results, the best thing to do is not cut your caloric intake so drastically. Not only will it result in more fat burning and less muscle loss, but you will feel better during the process. More importantly, it will be much easier to maintain the fat loss after you stop dieting. Always treat fat loss as a long-term project and don’t try to lose as much fat or weight as quickly as possible. When it comes to fat loss, slow and steady really does win out in the end.