Is there an energy surplus or energy gap?

Anyone who knows a little about thermodynamics can understand that there is a correspondence and transformation relationship between energy and matter. For example, for adults, if they do not exercise at all for a period of time and gain weight without any endocrine abnormalities, I can infer that there is actually an energy surplus (fat has grown, muscles have not grown without exercise). However, there are certain difficulties in accurately calculating the quantitative relationship between energy surplus and weight gain, as there are many uncertain factors involved

One is the ability to absorb and digest. Some people have very strong gastrointestinal function and absorb everything they eat, so the absorption rate is 100%. Others have weaker absorption ability and cannot achieve 100% absorption, so the utilization rate of food cannot be maximized;

Secondly, there is the ability to synthesize substances, especially the body's ability to use carbohydrates to synthesize subsequent substances (such as fat synthesis), which is also closely related to dietary structure;

Finally, there is the metabolic capacity of the body. For example, some people have a high basal metabolic level, while others have a slow metabolic rate. Therefore, the changes in their bodies when facing calorie surplus are not the same for these two types of people.

Of course, we can use simple models when analyzing problems, but the problem with simplifying models is that they may overlook many influencing factors. From a practical perspective, it is almost impossible to accurately calculate the impact of energy surplus/energy deficit on the body. In addition to the several influencing factors mentioned above, the energy measurement of food itself only uses thermodynamic methods. However, theoretically, not all substances that can generate energy can be utilized by the body (such as fiber, which has energy but cannot be utilized by humans, and denatured starch, which has energy value but cannot be absorbed and utilized by the body, and the deformation of starch is closely related to cooking methods). There are also some nutrients and micronutrients that affect the absorption, digestion, and metabolism of food energy, which can also change the impact of food energy on body composition.

The concepts of energy surplus/energy gap objectively exist, and you cannot deny the validity of the concept itself just because they are difficult to calculate. The use of these two concepts may be less likely to go wrong with the idea of "grasping the cause". For example, if an athlete maintains a stable training state, daily routine, and basic health status, and their weight increases, and the sebum clamp measurement method shows no significant change in body fat percentage, then we can attribute weight gain to "weight gain after removing fat" (why can't we directly obtain muscle gain? Please think about it).

After the confirmation of weight changes, it is necessary to verify again through changes in athletic performance in order to more accurately determine whether these changes are based on muscle growth. However, for athletes, the increase or decrease in lean body mass can have multiple effects on athletic performance (which may be positive or negative), and the choice of athletic performance indicators is closely related to the competitive events they engage in.

For ordinary people, I don't think it's inappropriate to use calorie surplus/calorie deficit to manage weight. For example, if someone feels that they have recently gained weight, they should eat less than half a bowl of rice per meal and reduce their oil intake. After a period of time, their weight will decrease. Therefore, this weight loss must be attributed to "controlling the calorie intake of the diet". If the consumption is greater than the intake, what is the difference? The core idea here is still to infer from the result to the cause. Diet, like training, is very practical. First, operate through practice to obtain the results, then analyze and iterate, and finally slowly move towards the goal. However, if you find a "Daily 500kcal Shortage Diet Plan" online, it may not necessarily achieve the effect of losing 0.5kg in a week because it contains 500 calories, not your 500 calories. (For specific reasons, please refer to the previous analysis). Do not have template thinking, as this is a sign of neglecting to think. Everyone's situation varies greatly, please find the most suitable method through practice.