Are we eating more because the food is low in vitamins and minerals?
We hypothesize that we overeat because modern food lacks vitamins and minerals. To get enough of them, the body stimulates us to eat more. In other words, we overeat and gain weight because the food does not cover the body’s needs for micronutrients. Is this true, and what does the science say?
It is known that both animals and humans choose food with certain properties. For example, people are attracted to foods high in fat, sugar, starches, and protein. Much less do we like low-calorie foods that don’t have all that. Most people would prefer carrot cookies.
In certain cases, the body detects a lack of certain substances and forces them to get them through food. For example, a semi-starved diet causes a person to constantly feel hungry and crave high-calorie foods as the body tries to compensate for the lack of energy. Protein-rich diets are more likely to crave foods high in protein. Man, like most animals, likes the salty taste because salt contains substances important for the body – sodium, and chlorine. True, today, many of us eat much more salt than the body needs. Sometimes we crave something sweet or sour. Everyone knows pregnant women’s strange addictions and aversions to certain products, although there are no exact explanations for this yet. Some animals can correct mineral deficiencies by choosing foods that contain the right substance.
These observations led to the hypothesis that the human body can determine its vitamin-mineral status and seek to replenish the deficiency. This leads to the second statement: “empty” food (one that does not contain anything useful except calories) leads to overeating – this is how the body tries to compensate for the low concentration of vitamins and minerals in food. In other words, we overeat because modern food does not cover the body’s micronutrient needs. At the same time, a diet rich in vitamins and minerals makes up for the lack of necessary substances and allows you to eat less and lose weight. All this is derived intuitively, and intuition is not exactly what helps to understand biology.
For the hypothesis of overeating to replenish vitamins and minerals to be true, the human body needs:
- Be able to assess your status across a variety of vitamins and minerals.
- To determine food’s vitamin and mineral composition – instinctively or as a result of training.
- Be able to create an incentive to consume those foods that contain the necessary vitamins and minerals or to eat more.
- Choose food primarily by vitamin and mineral composition and not by calorie content.
In general, I am not sure that there is scientific evidence confirming such abilities’ existence in humans. There is no doubt that vitamin and mineral deficiencies affect the body. Still, there is no evidence that this is the reason for changing eating behavior to compensate for the deficiency. Conversely, micronutrient deficiencies are usually associated with a decrease in appetite rather than an increase, which means that the body is not trying to make up for what is missing by forcing you to eat more. This also applies to animals that eat less and lose weight when deficient in micronutrients. But filling the deficit returns both appetite and body weight.
So far, it is known that the human body can detect a lack of calories and protein and respond accordingly – by stimulating to get more calories or protein. As far as vitamins and minerals are concerned, there is no evidence yet that such regulatory systems exist, that the body can determine the vitamin/mineral composition of food and respond by changing eating behavior to make up for the deficiency. But since some animals do it, we probably haven’t found a similar effect in humans yet.
We can define different properties of food that are indirectly related to micronutrients. For example, sweetness and acidity are associated with potassium and vitamin C (in natural foods). The taste and smell of cooked meat (glutamate and volatiles) are associated with B vitamins, iron, and zinc. Some animals can recognize which foods are mineral-rich and which are not. In modern nutrition, these natural habits are confused by added sugars, fats, glutamate, and flavorings that disrupt the natural relationship between taste/aroma and nutritional value.
Another issue related to the overeating obesity hypothesis as a result of vitamin and mineral deficiencies is that today’s Americans have relatively good vitamin and mineral status. We may not get the optimal amount of micronutrients, but the risks of real pronounced deficiencies are small for the most part because foods are often fortified.
The situation was different a century ago: thyroid disease (iodine deficiency), rickets (vitamin D deficiency), pellagra (nicotinic acid deficiency – vitamin PP), and scurvy (vitamin C deficiency) were common in some regions of the United States. However, at that time, obesity rates were lower than now—apparently, people weren’t eating more to make up for their micronutrient deficiencies.
To test hypotheses, we need controlled studies. The hypothesis will be proven if the study reveals the following:
- A slender person with a decrease in vitamins and minerals in food (without other factors) begins to eat more.
- A full person with an increase in vitamins and minerals in food (without other factors) begins to eat less.
According to the latter assumption, there are just studies. First, a group of overweight Chinese women took vitamin and mineral supplements. The scientists found no significant effect of supplementation on food choices based on calories, protein, fat, carbohydrates, or any of the 15 micronutrients studied. However, after 26 weeks of supplementation, the participants experienced a slight increase in calorie expenditure, a slight decrease in body fat, and improved metabolic and cardiovascular performance. This study does not support the theory that we eat to compensate for micronutrient deficiencies but suggests a curious effect of vitamin/mineral status on calorie expenditure, metabolic adjustment, and body weight (at least in overweight Chinese women).
In any case, the result should be critically evaluated: it is unlikely that the effect on metabolism was so significant, but seen before in other studies using vitamins and minerals in supplements.
Another interesting study combines observational and controlled randomized trials. An observational study found that people who regularly take multivitamin/mineral supplements tend to be leaner than those who do not. However, considering other factors, it can be said that their lifestyle is generally healthier. That is why it cannot be said that slimness results from taking supplements and not other factors.
Next, the scientists conducted a randomized controlled trial: obese men and women were randomly divided into two groups. As part of a 12-week weight loss program, one group took vitamin/mineral supplements, and the other received a placebo. Changes in fat mass and energy expenditure were similar in both groups. Both sexes had the same hunger, satiety, and expected food intake. Thus, a controlled study does not support the idea that vitamin/mineral status significantly affects appetite and body weight or makes weight loss more or less effective.
So far, there is little evidence that the human body can determine its vitamin and mineral status and manage eating behavior. Neither humans nor animals deliberately consume more calories to raise their micronutrient levels, nor do they consume fewer calories if the concentration of micronutrients in the food is increased. It is unlikely that the diet’s overall “density” of micronutrients plays a leading role in overeating. However, certain vitamins or minerals have a biological effect that tips the scales one way or the other.
If controlled studies are done, we may be able to learn more about human food choices based on the need for specific substances (we know that some animals can do this).
Eating micronutrient-rich foods is beneficial; it helps to lose weight, even if it is not directly related to vitamin and mineral deficiencies. Similarly, “empty” foods lead to overeating, not because of their low micronutrient content, but because they are tasty, more enjoyable, and less satiating. We are ready to eat it, even if we are not hungry, which leads to overeating and being overweight.