Where in the Brain Do We Decide What Food to Eat?
The brain is a complex organ with many different areas which work together to make us who we are. One area of the brain called the hypothalamus plays a crucial role in our emotions and behavior. The hypothalamus produces hormones such as adrenaline, noradrenaline, dopamine and serotonin which regulate mood, appetite and other functions. These hormones affect all parts of our body including our brains. For example, when we feel hungry or full, these hormones cause the release of digestive enzymes into the small intestine where they break down food so it can be absorbed into our bodies. When we are not feeling well, these same hormones may stimulate hunger and cravings to get us to overeat. If we don’t have enough energy to do this, then our bodies will turn to the pituitary gland (a small almond shaped structure located near the base of the brain) which releases growth hormone. Growth hormone stimulates cell division and helps increase blood flow throughout our bodies.
As you might expect, these hormones play a big role in regulating our eating habits. In fact, eating disorders such as anorexia and bulimia are caused by hormonal imbalances in the brain. For example, the small protein called neuropeptide Y (NPY) has the ability to decrease appetite and prevent overeating while leptin (produced by fat cells) has the opposite effect, increasing hunger and food consumption. These hormones also play a role in obesity, which affects over one third of Americans. Ultimately, the brain plays a powerful role in eating habits and what you eat has a direct effect on your brain.
The brain can be divided into two broad categories: the old brain and the new brain. The old brain consists of the brain stem and the limbic system while the new brain consists of the cerebrum and cerebellum. The new brain is further divided into sections called lobes. These sections are the frontal, parietal, occipital and temporal lobes. The new brain is closely linked to the old brain.
The cerebellum coordinates movement and balance while the cerebrum is responsible for learning, cognition and thought.
The exact location of where you feel fullness, hunger urges and cravings has not been conclusively determined. However, some researchers believe they have discovered where a few of these sensations are processed. For example, researchers from the National Institute on Alcohol Abuse and Alcoholism found that the hypothalamus contains a “hunger center” which is stimulated when you are hungry. In addition, they believe that areas of the limbic system such as the amygdala and nucleus accumbens also play a role in appetite. Certain parts of the frontal lobe of the cerebrum can also cause cravings for certain types of food.
For example, the orbitofrontal cortex is associated with an intense longing for carbohydrates while the cingulate gyrus is linked to a strong desire for fat.
The type of diet you choose to follow has a direct effect on these areas of the brain. In the next sections, we will look at some of the main types of diets out there and how they affect the brain.
Low-Fat vs Low-Carb Diets
The first thing you need to know is that there are two main types of diets: low-fat diets and low-carbohydrate diets. Low fat diets allow you to eat as much as you want as long as the fat content does not go above a certain percentage. Low carbohydrate diets, on the other hand, limit the amount of carbs you eat in a day.
These two types of diets affect the brain in different ways. For example, low fat diets tend to reduce levels of NPY (discussed earlier), which causes you to feel less hungry. Low carbohydrate diets, on the other hand, can lead to a decrease in dopamine and serotonin levels as well as raising stress hormones (which usually decrease during dieting). While low fat diets can cause nutritional deficiencies, low carbohydrate diets can also lead to vitamin and mineral deficiencies. Both types of diet can affect your brain.
Low-fat diets are one of the more popular diets out there. You do not have to count calories or weigh your food (as long as the fat content stays low). While these diets can be beneficial for people who want to lose weight, they also tend to reduce your levels of serotonin and dopamine, which can cause irritability, restlessness and depression.
Low-fat diets also tend to reduce fat soluble vitamin and essential fatty acid levels. For example, low fat diets tend to reduce levels of the fat soluble vitamin A, which is important for healthy eye function and vision. Low fat diets can also cause a reduction in melatonin, a hormone that helps you sleep.
Low-carbohydrate diets are one of the more popular fad diets out there. Many diets like the Atkins diet, the Protein Power diet and others advocate the consumption of large amounts of fat while restricting carbohydrates.
While low-carbohydrate diets can result in weight loss for some people, they tend to have a large number of side effects. Many doctors and dieticians believe that the side effects caused by these types of diets are not worth the weight loss.
For example, low-carbohydrate diets tend to lower your levels of the neurotransmitters serotonin and dopamine. Low serotonin levels are associated with depression, irritability and anxiety while low dopamine levels lead to poor concentration, lack of motivation and a general feeling of unhappiness. Both of these brain chemicals are linked to eating behavior; low levels can lead to binge eating and no desire to eat healthy foods.
Low-carbohydrate diets also tend to raise the stress hormone cortisol. Elevated levels of cortisol are associated with a negative mood, anxiety and weight gain. One of the main reasons people turn to low-carbohydrate diets is to lose weight and while some do succeed in this, most people who stay on them end up gaining the weight back (and then some). Part of the reason for this can be attributed to the constant elevation of cortisol that these diets cause.
Many low-carbohydrate diets, especially those of the ketogenic variety, can also lead to a severe reduction in essential vitamins and minerals as well as key electrolytes like potassium. This has been linked to numerous side effects like fatigue, light headedness, headaches and constipation.
Other low-carbohydrate diets aren’t quite as restrictive and allow some dairy and whole grains. This lowers the risk of side effects, but many people can’t tolerate these foods and end up with diarrhea, bloating and nausea.
The Bottom Line
While low-carbohydrate diets might work for some people, they aren’t necessarily better than diets that emphasize a reduction in fat intake. Both types of diet are capable of producing weight-loss.
Instead of thinking about a food as being “good” or “bad,” it’s important to concentrate on eating a balanced diet that consists of all the food groups. A nutritious diet doesn’t just prevent side effects; it also promotes weight loss and helps keep your energy levels and mood up.
So, what do you think about low-carbohydrate diets? What’s your take on the issue?
Let us know in the comments section below.
By Nikki Spartz | Updated April 3, 2019
© Deep Blue, LLC | 2013-2019 All rights reserved.
Sources & references used in this article:
To eat or not to eat-how the gut talks to the brain by J Korner, RL Leibel – New England Journal of Medicine, 2003 – researchgate.net
The Beck Diet Solution: Train your brain to think like a thin person by B Wansink – 2007 – Bantam
Your brain is (almost) perfect: How we make decisions by JS Beck – 2012 – books.google.com
How we decide by R Montague – 2007 – books.google.com
‘Liking’and ‘wanting’food rewards: brain substrates and roles in eating disorders by J Lehrer – 2010 – books.google.com
Inside the FDA: The business and politics behind the drugs we take and the food we eat by KC Berridge – Physiology & behavior, 2009 – Elsevier