Reducing Calorie Intake Makes Us Smarter

In diets with caloric restriction, the number of brain neurons related to memory grows, we orient ourselves better and capture more details of the environment.

CARMEN NOGUERA CUENCA Professor of the Department of Psychology / Basic Psychology. Research group HUM-891 Cognitive Neuroscience Research, University of Almería JOSE MANUEL CIMADEVILLA Professor of Psychobiology, Health Research Center, University of Almería

It is no coincidence that every time our body demands food intake, our mobility and mental agility increase. Over thousands of years of evolution, the biological mechanisms that ensure that we get enough nutrients for our body have been enhanced.

Specifically, food demand increases memory. Why? In essence, because it helps to cope with the lack of nutrients.

Among other things, with hunger our ability to orient ourselves in the environment, called spatial memory, increases. For our ancestors, this helped them to remember the path to reach that fruit-laden plant, or the river from which their potential prey drank.

caloric restriction improves memory

When nutrients are scarce, the first to wake up are the neurons of the hippocampus. It is a fundamental brain structure in our declarative memory, which allows us to say things like: "I remember that yesterday I had coffee and toast for breakfast." And it's also an essential part of our spatial memory so that when it's damaged, as it is in patients with Alzheimer's dementia, people don't remember what they did (declarative memory) and become disoriented even in well-known settings like their home (declarative memory). space).

Well, it has been shown that in diets with caloric restriction, the number of neurons in the hippocampus grows and its functionality increases. This makes it especially "sensitive" to changes in the environment so, in addition to orienting ourselves better, we capture more details of it. And of course, it is easier to survive.

It has recently been shown that intermittent fasting can reverse signs of cognitive decline. To prove it, the researchers worked for 36 months with 99 elderly patients, putting them through a calorie-cutting program. When the program ended, they not only lost weight but also reduced insulin levels and signs of inflammation. In addition, they returned to present a cognitive performance according to their age group, leaving behind all the signs of incipient cognitive deterioration.

Another advantage to keep in mind is that the hippocampus helps interpret internal feelings of hunger and coordinates behavior with the body's energy needs. Therefore, patients with damage to the hippocampus (bilateral hippocampal resection) can devour a meal and, if the same dish is presented next, eat it with the same voracity. It could be deduced that with caloric restriction we respond better to satiety signals.

Overfeeding, on the other hand, makes us clumsy

It seems indisputable that the lack of food helps our memory work better. But, could we also validate the opposite thesis? Is there evidence that overeating impairs cognitive functioning? Everything points to yes.

A recent review brought out that increased body mass index is directly related to a reduction in the gray matter of our nervous system, including the medial temporal lobe, where the hippocampus is located. Moreover, even in children it is possible to find a direct relationship between the effects of an inadequate diet (junk food with a high fructose content, abuse of ultra-processed foods, etc.) and a reduction in hippocampal volume.

Thus, the thesis that the current Western diet, rich in fat, increases neurodegenerative processes and reduces the formation of new neurons in the hippocampus seems to be proven.

The saying goes that “hunger sharpens the wit”. At the moment we have evidence that, at least, it speeds up memory. This does not mean that everyone should go hungry. But we should keep in mind that a balanced diet, which avoids excess calories, can help our cognitive system to function more optimally.

This article has been published in 'The conversation'.