400 kcal a day is not a lot of exercise.

For example: 7000 kcal of coal means that the calorific value of the coal is 7000 kcal/kg, which is equivalent to the engineering kcal/kg.

Unit of heat. 1 kcal = 1000 calories, mostly used in nutritional measurement and fitness manuals.

For example: if the temperature of 1kg pure water increases or decreases by 1 degree Celsius, the heat absorbed or released is 1 kcal. Kcal is kilocalories (formally speaking it should be kilocalories or kcal). Used to evaluate the quality of fuel, one kilogram of fuel can raise X kilograms of water by 1 degree Celsius, which means that the calorific value of this fuel is X kcal.

Generally, the daily calorie consumption of adults is about 2200-2400 kcal for men; about 1900-2100 kcal for women.

In order to maintain normal body temperature, blood circulation and breathing, the human body consumes more than 1,200 kcal of energy for its basic functions. Therefore, normal healthy people will not consume only 400 calories in 24 hours.

Adults need at least 1,500 calories of energy per day to maintain body functions. This is because even if you are lying still, the body still needs energy to maintain body temperature, cardiopulmonary function, and brain function.

Extended information

Note:

Basal metabolic consumption will vary depending on individual differences in height, weight, age, and gender. Humans need energy to survive and obtain this energy from food.

1 calorie is equal to 4.2 joules. Calorie unit conversion: 1 kilocalorie (kcal) = 1 kcal = 4.1868 kilojoules (kJ) = 1 calorie/g.

The relationship between it and Joule is: 1 cal 20℃=4.1868J.

Some countries use cards at 15°C. Its relationship with Joules is: 1 cal 15°C = 4.1855J.

Baidu Encyclopedia-Kcal