Weight Loss: Customized Calorie Consumption Prescription for Scientific, Safe, and Resilient Fat Reduction

I. Balance Between Calorie Intake and Consumption

(I) Calories and Their Units Calories are the portion of energy converted or transferred in a microscopic form.

The unit of calories is generally expressed in kilocalories (kcal). It refers to the amount of heat required to raise the temperature of 1 kilogram of water by 1°C. Internationally, joules are also used.

(II) Daily Calorie Needs of the Human Body and Their Sources The metabolism of matter and energy in the human body and the external environment proceed synchronously. On the one hand, the human body obtains calories from the food it needs (only the three major nutrients—carbohydrates, fats, and proteins—provide calories); on the other hand, it supplies calories to the muscles, internal organs, and brain, as well as to maintain a constant body temperature. Everyone should strive to maintain a balance between calorie intake and calorie expenditure. Ingesting more calories than expends will lead to fat accumulation and weight gain; conversely, it will lead to weight loss. Many people now exhibit a tendency towards calorie imbalance. Observations show that older people and children, especially women, experience more significant weight gain. This is the inevitable result of excessive calorie intake from food coupled with a lack of necessary exercise or physical activity. We often hear people say, "It's hopeless, even drinking water makes me fat." This is, of course, a joke. In reality, obesity and thinness are generally the result of accumulated factors over time. If the calories consumed from food exceed the calories burned, fat will accumulate over time, leading to weight gain; conversely, if the calories consumed are less than the calories burned, a person will become thin. Therefore, obese individuals must maintain a negative calorie balance between calorie intake and calorie expenditure, meaning that calorie intake should be slightly less than calorie expenditure, in order to successfully lose weight. Those who truly believe that "drinking water makes you fat" should try it for a week: eat only one bowl of porridge with pickled vegetables for each of their three meals, and see if they lose weight.

Currently, there is no systematic data available in China regarding the daily calorie requirements of the human body. Internationally, the recommended intake is typically determined by standard weight and the nature of the work: 25-30 kcal/kg body weight for those at rest without physical activity; 30-35 kcal/kg body weight for those engaged in light physical labor; 35-40 kcal/kg body weight for those engaged in moderate physical labor; and above 40 kcal/kg body weight for those engaged in heavy physical labor. However, obese individuals should reduce their intake accordingly, up to 1200 kcal/day depending on their purpose and needs.

(III) Example of Calorie Intake Calculation Calories are obtained from food. We will calculate the calorie intake based on the calories provided by staple foods and side dishes as follows:

1. Staple Food (Rice as an example): According to measurements, every 100 grams of rice contains 74.6 grams of sugar, 2.5 grams of fat, and 8.3 grams of protein. Every gram of sugar and every gram of protein provides 4 kcal, and every gram of fat provides 9 kcal.

2. Taking beef as an example: According to measurements, every 100 grams of beef contains 35.3 grams of fat, 15 grams of protein, 0.7 grams of minerals, and 40 grams of water. Minerals and water do not directly provide calories.

Therefore, fat 35.3 (g) × 9 (kcal) = 317.7 kcal.

protein 15 (g) × 4 (kcal) = 60 kcal.

100 grams of beef provides 377.7 kcal of energy.

Most foods that can be consumed by humans can be calculated using the above two examples.

1. Factors Affecting Calorie Consumption: Many factors influence calorie consumption, such as age (internationally, the method used is to reduce calorie supply with age, based on a calorie supply of 65 kg for men and 55 kg for women aged 20-89; 5% reduction for 40-49 years, 10% for 50-59 years, 20% for 60-69 years, and 30% for those over 70 years), gender, occupation (Table 3-4), duration of activity, climate (based on 10°C, 5% reduction for every 10°C increase in temperature; conversely, 5% increase for every 10°C decrease in temperature), body type, etc.

Chinese researchers have measured the daily calorie consumption (kcal/day) of certain occupational groups in my country as follows: male university students 2400, female university students 2170, suburban female vegetable farmers 2770, steelworkers 2857.2-394.5, and tungsten miners 2600-4700.

A former Soviet Union textbook on physical education theory stated: "Those engaged in heavy physical labor and advanced athletes consume more than 7000 kcal per day. Among athletes, the 100km skier consumes the most energy, reaching more than 10000 kcal per day."

2. Calorie Consumption Calculation

(1) Formula Calculation Method: The renowned Soviet physiologist, Dr. Lev Ivashko, developed a formula for calculating calorie consumption during physical exercise. This formula is suitable for all sports except swimming. Calculation formula: Calories consumed (kcal/min) = (0.2 × maximum heart rate during exercise - 11.3) ÷ 2

Example: A woman's maximum heart rate during walking is 128 beats/min. Calculate the calories consumed during her half-hour walk.

Substituting her maximum heart rate into the formula, we find that she consumed 208.5 kcal during her half-hour walk.

(2) Coefficient and weight product method: In recent years, some nutritionists abroad have successfully developed a method to assess daily calorie consumption by multiplying a coefficient (35) by body weight for individuals engaged in light physical labor. Calculation formula: Calories consumed (kcal/day) = Coefficient (35) × Body weight (kg)

Example: A young man from northern China, engaged in light physical labor, is 175 cm tall and weighs 65 kg. Calculate his daily calorie consumption.
Substituting his actual weight into the formula, we find that he consumes 2275 kcal daily.