[China Packaging Network News] Food labels seem to provide all the information consumers need, so calculating the calories of food should be very simple.
But things are not so simple because the information on food labels is not complete.
Calories are a measure of available energy. The food label shows how many calories the food contains, but the question is — how many calories you actually can absorb from it depends on how well you process the food.
Processed foods make you fatter
The food processing process includes cooking, mixing and mashing, as well as the difference between using refined flour or unrefined flour. The processing may be done by a food processing plant before you buy it, or it may be done by you at home. This process has a great influence. If the food you eat is unprocessed, you may lose weight; and if you eat these foods later, you may gain weight. The same calories, not the same result.
For our ancestors, this may mean the difference between life and death. Hundreds of thousands of years ago, when primitive humans learned to cook, they could get more energy from food. This extra energy allows them to form larger brains, reproduce more quickly and migrate to more distant places. Without cooking, we will not evolve into humans.
More processing = more complete absorption
Animal experiments have shown that, regardless of the energy source of carbohydrates, proteins, or lipids (fats and oils), processing can affect calorie acquisition. The deeper the processing, the more energy the consumer can obtain.
For example, carbohydrates, they provide almost half of the world's calories. Their energy is often contained in the starch of the grain and will be broken down into glucose, which is mainly digested by the small intestine. If you eat unprocessed starchy food, half of the grains may pass through the small intestine without being digested at all. Your body can only get two-thirds of the calories it eats, or even less. The rest of the energy may be used by the bacteria in the colon or it may be excreted.
Even if it is cooked food, the degree of digestion is not the same. If the starchy food cools after cooking, it will become less digestible because it will crystallize into a structure where digestive enzymes are not easily broken down. So stale foods, such as spaghetti or cold toast bread made the previous day, will give you fewer calories than freshly baked foods, although technically they contain the same amount of energy.
Softer foods also save more calories
Finished foods are not only easier to digest, they are also often softer, and the body needs less energy to digest them. The researchers fed rats two different laboratory foods. A form that is made into a small hard ball, that is, a form that is usually fed to a laboratory animal. The only difference is that the hard ball contains more air, like a puff. Rats that consumed both foods ate the same amount of food each day, the calories contained in the food were the same, and the amount of daily activity was the same. However, compared with rats eating hard food, rats that consumed soft food grew more heavily and had 30% more body fat.
Rats who eat soft foods get more energy because their stomach and stomach do not need to work so hard: Soft foods are easier to decompose. When rats eat, their body temperature rises due to digestion. Compared with eating the same amount of hard food, body temperature rises less when eating soft foods. Because eating soft foods requires less energy, rats that eat this food gain more weight and fat.
Our human body works in the same way. When eating foods that have been cooked, crushed, or inflated, the body needs less work. Imagine you are sitting at a festive table or dining in a luxury restaurant. Our favorite foods are carefully placed in front of you and the entrance is ready for you. You don't need to chews and slide into your throat. We all like this enjoyment. What we prefer is the natural way to preserve precious calories as much as possible.
Why can't food labels tell you all the information?
Of course, unfortunately, this natural approach is no longer the best way for people who are not worried about food and clothing today. If we want to lose weight, we must challenge the instinctual desire. We should reject the soft white bread and choose rough wholemeal bread; reject processed cheese and choose natural cheese; refuse cooked vegetables and choose to eat raw vegetables. And if the food label can tell us how much calories can be eaten less with less processed foods, losing weight will become more effective. Why do nutritionists keep silent on this issue?
For decades, various expert committees and associations have been calling for reforms to calorie calculations, but these appeals have had no effect. Because researchers found it difficult to calculate precisely how many calories we would consume when we consumed a more processed food. Instead, they found that it is very easy to calculate the specific number of calories that can be obtained if a certain food is completely digested.
Therefore, in the production of food labels, one of the two methods should be selected, which is not perfect. The first method can give accurate calorie numbers but does not consider the effects of known food processing, so it is impossible to measure how many calories our body can actually get from food. The second method considers the effects of food processing but does not give any accurate figures.
In the face of this dilemma, each country has chosen to ignore the impact of the processing process, and the result has been consumer confusion. The number given on the food label is likely to overestimate the calories the body can obtain from raw food. Food labels do not consider the cost of the digestive process - that is, the energy loss caused by bacteria and the energy consumption of the digestion process. For processed foods, these two costs are lower, so the label of processed foods has less overestimation of calories.
Is it time to make a change?
Since it is important to accurately calculate calories, it is time to start the discussion again. A label similar to “traffic light†should be used on food labels to tell consumers whether the food is deep-processed (red), light-processed (green), or in the middle (yellow).
For public health needs, consumers should be made aware of how the way we process food affects weight. Calculating calories is very important, and we can't tolerate a clearly not the best labeling method. We need to invest more scientific effort to calculate how much food processing affects the number of calories available.