Generally, it can be found from the food composition table, or it can be accurately measured by a calorimeter. Put the sample to be measured into the combustion chamber of the calorimeter for complete combustion, and use water to absorb all the released energy. When one milliliter of water rises once at normal pressure, it needs to absorb 4. 187 Joules, record the changes of water quality and water temperature, and convert accordingly.
The heat of food samples is defined as: 1ml (with the mass of 1g). The heat required for each increase of 1 degree Celsius is 4.8 17 joules when heated. [ 1]?
(1) Staple food: such as rice, porridge and noodles. If 80 kcal is used as a unit of calculation, the calories of a bowl of rice, porridge or noodles of ordinary size commonly used in daily life are equivalent to 80 kcal.
② Meat, tofu and eggs: 37 grams of lean meat and 20 grams of fat meat are 80 calories. 125 grams of milk, two teaspoons or half a tablespoon of oil are all 80 calories. It is worth noting that 1 boiled egg has 80 calories, but 1 fried egg has 120 calories.
3 Vegetables: 600 grams of any vegetable is equal to 80 calories.
④ Seafood:100g is about 80 calories.
⑤ Fruits: 300 grams of watermelon and 2 oranges are 80 calories.
Extended data
1 What is heat? The human body consumes energy all the time, which is provided by thermogenic nutrients in food. Nutrients that can generate heat in food are protein, fat, sugar and carbohydrate. They are oxidized to generate heat for the body to maintain life, grow and develop and exercise. When the heat energy supply is too much, the excess heat will become fat and be stored. After a long time, the body will get fat.
2, the unit of heat: in nutrition, use "kilocalories" as the unit of heat. 1 kcal is the heat required for 1L water to rise from 15℃ 1 degree.
There are three main ways of calorie consumption. The first part is basal metabolic rate, which accounts for about 65-70% of the total calorie consumption of human body. The second part is physical activity, which accounts for about15-30% of the total calorie consumption. The third part is the thermal effect of food, which accounts for at least about 10%. The proportion of these three has been basically fixed.
Unit of heat: calories, 1 calories = 1000 calories.
Nutrients that can provide calories in the diet are sugar (carbohydrate), fat, protein, alcohol, organic acids and so on. The calories they contain are: 4 calories for sugar (carbohydrate), 9 calories for fat, 4 calories for protein, 7 calories for alcohol and 2.4 calories for organic acid.
To calculate the calories contained in food or diet, we must first know the weight of calorie nutrients, and then use the following formula to calculate:
Calories (kcal)= grams of sugar× 4+grams of protein× 4+grams of fat× 9+grams of alcohol× 7.
The heat consumed by adults is utilized in three aspects: basal metabolism, activity and food thermal effect; Additional calories are needed for tissue construction during growth and pregnancy.
References:
Baidu Encyclopedia Food Calorimeter