Do We Absorb 100% Calories / Nutrients in Food ?

Such a question might have raised in your mind some day. Every engine have an efficiency rate. There is no engine with a 100% efficiency rate. Then how can a human absorb all the energy stored in the food ? Is our stomach the only place where calories are absorbed ? If we can't absorb the 100% Calories then how do food manufacturers write nutrient information on packets ? If we totally depend on that information then it might make us suffer from malnutrition. Here will try to answer such questions with true scientific answers researched from internet.

Do We Absorb all Calories and Nutrients in Food ?
The straight answer in No. We can't absorb all calories and all nutrients of the food that we eat. Various factors affect the amount of calories and nutrients that your body can absorb from a food that you have just eaten. Some of the factors are:

  • The time of the day
  • Either the food is raw or cooked
  • Is there any supplement added in it
  • Even your age can affect
  • Need of a particular nutrient
We absorb 10 to 90% of nutrients and calories from a food depending on the factors written above. But on an average we absorb 85 - 90% of calories and nutrients from our diet. Our body can itself change its absorption rate depending on its need. Sometimes it can avoid the absorption of a nutrient which is already in sufficient amount in body. But sometimes it becomes more efficient in absorption of a particular nutrient if there is any shortage of that nutrient.
Note: Our eating habits also make impact on nutrient absorption. An article about Acidity and Antacids published on will put some light on this particular topic. Its a must read for all health conscious people. 

How does time of the day affect calorie / nutrient absorption ?
All other factors written above make some sense, but how do the time of the day affect the absorption. Our biological clock or circadian rhythm, a 24 hour cycle in our brain affects our absorption rate. Some enzymes and hormones reach their peak at different times of day and help in absorption of different nutrients. For example parathyroid hormone, which helps in absorption of calcium, reaches its peak during night time. Due to that reason some people suggest taking milk before going to bed, as it can help in better absorption of calcium from milk.

Is our Stomach the only organ responsible for nutrient absorption ?
No, Stomach is a part of large digestive system in our body. Every organ starting from mouth to large intestine play an important role in the absorption of nutrients. Our mouth produces saliva and mixes it with food to break it down, further stomach mixes and churns it and breaks carbohydrates proteins and fats. But the main organ to do absorption is small intestine which absorbs amino acids, fat, proteins, cholesterol, vitamins and minerals such as calcium, magnesium, iron, chloride, sodium, zinc and many more. Further large intestine absorbs remaining water, sodium and potassium. Fiber in the food remain undigested and helps in bowel movement.

Where are the calories lost and remain absorbed ?

  • Some calories are consumed by the bacteria living in our gut.
  • Some calories are flushed out through urine.
  • Some calories remain absorbed from the food due to various factors listed above.
But still all of the above wastage of calories only account for a maximum 10% loss.
Acidity and Antacids can greatly affect the absorption of nutrients. You may read our article Acidity and Antacids are making you Unhealthy for more information.

If we can't absorb the 100% Calories then how do food manufacturers write nutrient information on packets ?
The nutrient information written on the packets is the average calorie / nutrients that your body can absorb. But as we said earlier that various factors affect that absorption, its not just the food. Even the nutrient information written on package is just an average value. Nutrient value of a food depends on various factors given below:

  • the quality of soil where that food is grown
  • amount and quality of fertilizers used
  • quantity of water used for irrigation
  • the breed/variety of the seeds
  • the pesticides used
  • the environmental conditions of that particular season

You can't check nutritional value of each food product before packaging, so the manufacturers just print the average value from their database. Apart from that the duration from which that food product is lying packed in the packet also affect its nutrients.

Can we stop / reduce calorie absorption ?
Yes we can do it up to some level. There are various food items that can both enhance or reduce the absorption of some nutrients. But most of us eat them unintentionally. If you will try to do it intentionally in order to reduce calorie intake, you will harm yourself by reducing some important nutrients in your body. If you want to do that to reduce your weight then its better to get your diet planned by by dietitian. Here we have mentioned some food items that affect the nutrient absorption.

  • Tea or Spinach can reduce / stop the absorption of calcium and iron from the foods that we have just eaten, due to presence of oxalates in them.
  • Olive oil can enhance absorption of carotenoids, which is an important nutrient for good health.
  • Phytic acid found in some grains and legumes can reduce absorption of minerals.

If you are on dieting, then rely of a single food to reduce your weight. Have a balanced diet by changing the fruits and vegetables so that you get all nutrients.

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