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Should You Lose Fat and Build Muscle at the Same Time?

  1. What is fat loss?

For most people, weight loss manifests itself in two aspects. The first is weight reduction. Many fitness beginners or most people’s understanding of fitness, weight loss or exercise starts with the number on the scale. With the popularization and improvement of fitness knowledge concepts, people gradually realize the importance of weight loss, or to be precise, fat loss. After all, too much fat is not a good thing.

Physiological principles

    First of all, it must be clear, because the relationship between muscle gain and fat loss must come down to physiology in the end. First of all, for weight loss, it is equivalent to an alienation effect. The so-called alienation effect is to turn something already in your body into something outside your body, a bit like taking out the money in your wallet and spending it. This is a catabolism, which is a negative energy balance, meaning that the energy you take in every day is less than the energy you expend every day.

    Operation method

      Traditionally speaking, the most classic way to lose weight is long-term endurance exercise, which is mainly characterized by large training volume, medium to low intensity, or even low intensity. Low intensity is mainly suitable for middle-aged and elderly people or fitness beginners. Young people are transitioning from low intensity to medium intensity, or even medium to high intensity. Generally speaking, the training frequency for fat loss is higher. Because it requires long-term total energy consumption, the recommended frequency is six to seven days a week, which is quite high. The answer given by the American College of Sports Medicine (ACSM) is to train at least five days a week, and it is recommended to train seven days a week. The lower limit of each time is 30 minutes and the upper limit is 90 minutes. In fact, there is no upper limit. In addition to sports, this also includes physical activity. For most people, the training intensity for fat loss is about one hour a day, six to seven days a week, which is still good.

      The most important thing about losing weight is the negative balance of energy. In addition to increasing consumption through exercise, the most important thing for negative energy balance is to control diet. If you don’t control your diet, the energy gap in your body will cause appetite in your nervous system, and you will keep eating. As energy is consumed, dietary intake will also increase, so a negative balance cannot be achieved. Although the body will get better, it will not show fat loss or weight loss. Therefore, in the process of losing fat, you must combine training with diet control.

      Let me add a sentence here. My teacher’s theory back then was to practice hard, eat as much as you want, and be more willful. At that time, I felt young and reliable, but now I can’t stand it anymore. Here, I would like to express my highest apology to the friends who were deceived by the editor and teacher back then! Let me reiterate, if you want to lose weight, practice steadily and control your diet. This is the rule and must.

      Physiological adaptation

      Training methods for weight loss in the traditional sense are basically long-term, continuous, low-intensity endurance exercises. The physiological adaptations brought about by these exercises basically allow your body to develop towards an economic adaptation. In other words, the energy consumed per unit of movement will decrease, and excess body fat, or excess weight, will decrease over time and as exercise increases. At the level of fluid regulation, levels of cortisol, a typically pro-catabolic hormone that inhibits muscle synthesis, increase.

      In terms of muscle adaptation, these long endurance events often primarily affect slow twitch muscle fibers. At the beginning, the slow-twitch muscle fibers may expand adaptively, but with further training, these expanded muscles will also atrophy to a certain extent. Because it has to adapt to a long-term consumable state, and then become more economical and efficient, redundant things will be removed. This is why those marathon runners and long-distance endurance skiers are thinner, but every muscle is the most essential part left. Because of these physiological adaptations, it is decided that if this form of training is used to lose weight, the development direction will be towards thinness.


      The physiological principles of weight loss are dissimilation, catabolism and negative energy balance.

      Its operation method is long-term continuous endurance exercise, medium and low intensity, high training frequency, and combined with diet control.

      The physiological adaptation to weight loss is often the development of economy. Cortisol levels increase, which mainly affects slow-twitch muscle fibers and inhibits muscle growth.

      1. What is muscle gain?

      There is no absolute synchronization between muscle gain and fat loss. The so-called absolute means that the total fat content is decreasing and the total muscle content is increasing. Overall, the body fat percentage is in a state of sharp decline, that is to say, I have become thinner and stronger. No matter how you say it, this is just a dream.

      Physiological principles

        The physiological principles of muscle gain and fat loss are basically opposite. The first is assimilation, promotion of anabolism, and positive energy balance. Its target is muscle, and the core substance is protein.

        Operation method

          The operation method of building muscle is relatively simple, and everyone actually knows it. For example, the classic method is resistance training of medium to high intensity. The frequency of training is moderate, a combination of work and rest, and there should be time between training for each muscle group. certain time interval. In fact, in each training session, the actual work time is not long. Counting intervals, rest between large groups, and adjustments, the actual practice time is less than one-third.

          In terms of diet, sugar supplementation is generally needed, because sugar supplementation can carry more training, and protein supplementation is required. Protein supplementation can synthesize the structural materials of muscles and allow muscle growth. So this is an anabolism, a positive balance of energy. This is the exact opposite of fat loss.

          Physiological adaptation

          The physiological adaptation of strength training and long-term aerobic training, that is, fat loss, are also completely different. First of all, strength training is an adaptation to pressure. People have a characteristic that the more pressure they get, the stronger they become. The greater the pressure, the more likely you are to push your limits. Levels of testosterone then increase, the classic anabolic hormone that promotes muscle growth. In addition, the main target of strength training is mainly fast-twitch muscle fibers. The expansion and growth rate of fast-twitch muscle fibers, and the adaptation performance in these aspects, are significantly greater than those of slow-twitch muscle fibers. So the result of strength training is that people become stronger.


          The physiological principles of muscle gain are anabolism, anabolism, and a positive balance of energy.

          Its operation method is classic high-intensity resistance training, moderate frequency, a combination of work and rest, and at the same time increasing the intake of sugar and protein with the diet.

          The physiological adaptations for muscle gain are often stress adaptations, increasing testosterone levels, promoting anabolism, developing fast-twitch muscle fibers, and becoming stronger.

          The above briefly introduces the physiological principles and training methods of fat loss and muscle gain. Of course, the introduction is relatively classic, excluding the commonly used cross training, HIIT and the like.

          Next, let’s make some comparisons between fat loss and muscle gain:

          High-intensity training is often used to build muscle, and low-intensity training is often used to lose fat;

          Muscle gain is often short-term intermittent training, while fat loss is often long-term continuous training;

          Muscle gain is generally done at a reasonable frequency, while fat loss is generally done at a higher frequency, six to seven days a week, or even continuously, like the editor is doing now;

          Strength training and resistance training are the main methods for muscle gain, while endurance training is the main method for fat loss;

          Building muscle mainly stimulates fast-twitch fibers, while losing fat stimulates slow-twitch fibers;

          Muscle gain mainly produces testosterone, and the secretion of testosterone promotes anabolism. Fat loss mainly produces cortisol, which is mainly a hormone that promotes catabolism.

          Gaining muscle will make you stronger, losing fat will make you more economical.

          1. Can fat loss and muscle gain be synchronized?

          Here I would like to share a passage from the “ACSM Guidelines for Exercise Testing and Exercise Prescription”. “Resistance training cannot prevent the loss of lean body mass and the decrease in resting metabolic rate during fat loss, but it can develop muscle strength and function and achieve additional health benefits.”

          Therefore, generally speaking, absolute synchronization of fat loss and muscle gain basically does not exist.

          The so-called absolute, the total fat content is decreasing, and the total muscle content is increasing. Overall, body fat percentage has dropped sharply. In other words, becoming thinner and stronger at the same time, no matter how you put it, this is just a dream.

          Here’s why:

          1. Because their physiological adaptations are completely opposite. For example, fat loss generally requires reducing energy intake. During fat loss, we will eat less and exercise more. If we feel hungry for a long time or even continuously, we will be very unhappy and irritable. For example, I am very irritable right now. Building muscle requires increasing protein, or even additional supplements. For example, some people now take protein powder. This is a typical example.

          Some people will ask, is it possible to gain muscle and lose fat simultaneously with a low-carbohydrate, high-protein meal plan?

          a. The problem of absorption. Carbohydrate is a very economical energy substance. It is absorbed very quickly, and the absorption process does not consume energy. Protein is a very complex structure that needs to be decomposed before absorption. After decomposition, it needs to be transported into cells. The transport process requires energy. Generally speaking, consuming high-protein meals or high-purity protein powder on an empty stomach is basically useless. It will only cause poor digestion, produce smelly decomposition products, and will not have a good protein-supplementing effect. Because it can’t absorb it at all. Here is a little common sense. The so-called sugar-free pure protein powder is unreliable. It is basically used to fool girls. Moreover, when choosing protein powder, it is strongly recommended to use protein and carbohydrates, or with Protein powder with a relatively balanced sugar ratio, or additional sugar may be needed.

          b. Conversion problem. Because man is a very magical animal. As an animal, our basic attributes are survival and reproduction. Therefore, when a person is hungry and eats something, the body will consciously and reflexively use a large part of it as stored energy, that is, it will be converted into fat. Because the external signal to it is that I am very hungry now, the body will think that you are in a state of famine. So every time something is ingested, the body will automatically store part of it and use the other part as current supply. Therefore, even during the fat loss period, when eating high-protein meals, the protein consumed will be converted into basic energy storage. In this case, the effect of protein supplementation on muscle gain will be very poor.

          c. Problems with metabolites. This kind of diet is the most economical because the intake of carbohydrates is very small. The only metabolic products of this economy are water and carbon dioxide, which are the direct decomposition of carbohydrates. They are very clean. However, protein contains nitrogen, including fat, which will increase people’s ketone bodies and have a negative impact on the body’s internal environment. So if you are a low-carbohydrate dieter, the internal environment of your body may not be very good, your endocrine system may not be very good, you may have bad breath, your skin will be dull and dull, you may get acne, etc. These are all metabolic problems that occur after unclean or impure food enters the body.

          d. Issues with training quality. Training quality cannot be guaranteed. Because the fat loss method we advocate is to control diet and strengthen exercise. Moreover, generally speaking, although diet control is good for losing fat, training can really bring you sustained health benefits. Therefore, we tend to pay more attention to training. If the training cannot be guaranteed, the training quality is not high and the training time is very short, this is not the method we advocate. This tends to happen with low-carb diets. Because the energy supply chains of fat and protein are very long and require very complex pathways to achieve, it is difficult for them to replenish the energy supply for medium- and high-intensity training in a timely manner.

          The above four points are counter-evidence explanations for those who want to achieve simultaneous muscle gain and fat loss by eating low-carbohydrate and high-protein meals.

          1. What makes it difficult to synchronize absolute muscle gain and absolute fat loss is the incompatibility between anaerobic and aerobic. The editor has written an article specifically about this before. Because anaerobic training, also known as resistance training, stimulates the human body in addition to physiological changes, as well as the nervous system. The same goes for aerobic training. These two training methods have effects on the nervous system. The stimulation is opposite. If they are mixed together, if the proportion of both is large, then aerobic training will dilute the efficiency of anaerobic training. In other words, if you practice strength but are diluted by aerobic exercise, you may gain 50% or even less. In this case, the overall performance is an aerobic performance. Therefore, the training efficiency is very low, and it is impossible to achieve simultaneous muscle gain and fat loss. It may make your fat loss effect better, but the muscle gain effect is very poor, or even negative.
          2. Simply using strength training to affect body fat may seem feasible, but it has its own shortcomings. First of all, the training volume will be very, very large and the cycle will be very long. This method is more suitable for boys, because boys pay more attention to body shape rather than weight, and the result of this kind of training is often weight gain. Moreover, the so-called long cycle is often measured in years, the training volume is large, the training rate may be every day, or even once or twice a day, and the training volume is repeated five or six hundred times a day or even higher. For example, the editor used to have a streamlined training plan, 480, which combined heavy weight training with light weight training. If strength training is to be used to affect body fat, it may require heavy weight training to achieve this.

          Although the absolute synchronization of muscle gain and fat loss does not exist, the relative synchronization of muscle gain and fat loss does exist.

          What is relative? Generally speaking, we calculate based on proportions. For example, the proportion of fat is 20%, but the total fat content has not changed, and the total muscle content is increasing. So the proportion has changed, maybe the fat has become 10%, or 15%, this relative change exists. Another relative is that, for example, during the process of fat loss, the fat content may be reduced by 3%, and the muscle content may be reduced by 1%. In this case, the overall proportion reflects the decrease in body fat, and the performance is also relative. Synchronized muscle gain and fat loss.

          1. Generally speaking, during the fat loss period, in addition to long-term endurance training, you may maintain strength training, or arrange some more trendy practices to achieve continuous energy consumption by increasing the density of strength training. In this case, it not only consumes energy, but also stimulates the muscles. As long as you combine it with balanced nutritional supplements, muscle consumption will be slower than fat loss. The so-called slower means that muscles will still be consumed, but the proportion will change significantly, which also shows that relative muscle gain and fat loss exist simultaneously. To give a typical example, a bodybuilder, during the off-season, is basically a fat man. He is very strong and very big, but his sebum is also very high. But when they prepare for the season, they will dehydrate and skim fat. Their muscles and fat are consumed simultaneously. However, fat is consumed very quickly, but muscles are consumed relatively slowly. In the end, Basically, only the muscles will be left, but the muscles will be much smaller.
          1. It focuses on building muscle, but arranges relatively comprehensive training. As the muscle body increases, the total amount of fat may slowly decrease, may remain, or may slowly increase. However, due to the rapid muscle gain, local fat will be diluted, and the overall proportion will also decrease. The body will appear stronger, the fat content will appear to be less, and the sebum will be thinner, but the overall fat content may not be significantly reduced, or may even increase. This is a phenomenon where the so-called muscle gain and fat loss are simultaneously focused on muscle gain. This is particularly common among male bodybuilders, especially male bodybuilders.

          It is possible to gain muscle and lose fat simultaneously at different training levels.

          For example, it is almost impossible for high-level bodybuilders to simultaneously gain muscle and lose fat, unless they take drugs, because they have already pushed themselves to the limit.

          1. But for ordinary people, or for young fat people, the possibility of achieving simultaneous muscle gain and fat loss is very high. We often see a very fat person, weighing about 200 pounds, start to exercise, run, and lift weights in a certain pattern. Over time, his body has changed significantly. His shoulders have become wider, he has become stronger and more powerful, and his overall sebum and fatness have decreased. The change in weight may not be as big as the external change, but it is already Quietly achieving the legendary synchronization of muscle gain and fat loss.
          2. Another group of people are frail men. They are very frail, but they may not be thin and their sebum content is not low. For example, some programmers and office white-collar workers are in this state. When these people start to exercise regularly, they may start with strength training because they don’t look that fat. They ignore aerobics or don’t pay attention to aerobics. If they practice for 3 months to half a year, they will find that they become fatter. If they become stronger, have lower body fat, and gain weight, then this kind of person can also quietly gain muscle and lose fat at the same time.

          A typical characteristic of these two types of people is that their basic abilities are very poor. Whether it is from the perspective of comprehensive physical fitness, physical condition, body shape, or body fat percentage, it shows that they are in a fairly pseudo-healthy state. For these people, there is a lot of room for improvement. They are like gold mines exposed on the ground. With a little digging, you can unearth many valuable things. In other words, they are very malleable. These people will maintain this miraculous effect of gaining muscle and losing fat simultaneously over a period of time. But it won’t last long. Generally speaking, after practicing for half a year, when they have obvious changes, it will be difficult and you need to make a choice.


          • There is no absolute synchrony between muscle gain and fat loss. The most fundamental reason is that they are two different sets of neural adaptations and physiological adaptations.
          • The relative synchronization of muscle gain and fat loss can be achieved. The muscle system that focuses on muscle gain increases and fat is diluted; the other one focuses on fat loss while maintaining a certain amount of strength training to maintain slow muscle consumption. Then, the fat consumption rate is faster than the muscle consumption rate, and the overall proportion is improved.
          • At different levels and under different conditions, it is possible to gain muscle and lose fat simultaneously. These people are mainly novices with very strong plasticity.