Health Blog

Food And Your Mood: The Serotonin Connection

Posted in Health Articles by Pulse Health Screening on June 7, 2010
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by Guest Author, Christian Finn

Do you ever find yourself sitting on the sofa with a bar of chocolate when you’re feeling stressed, bored, or just lonely? Or find that you get cravings for certain foods – such as cookies, bread or pastries – even when you’re not hungry? If you answered “yes” to either of those questions, I’m about to explain why it happens… and what you can do about it.

Food and mood

Many people turn to food for reasons other than physical hunger. They put this down to a lack of discipline, get very “down” on themselves… and then eat even more so they feel better again. This is a little like getting a flat tyre, jumping out of the vehicle, and shooting out the remaining three tyres!

What they don’t realize is that in many cases, these cravings could be due to a drop in the levels of serotonin in the brain. In fact, some studies show a direct link between obesity (due to overeating) and decreased brain serotonin levels.

What is serotonin?

Serotonin is a type of neurotransmitter known as a monoamine. Neurotransmitters are chemicals that send messages from one nerve cell to another. In short, a neurotransmitter helps different parts of your brain “talk” to each other. Without adequate levels of serotonin, you’d probably suffer from depression, sleep disorders, and various addictions.

It might also interest you to know that nicotine increases serotonin levels. Nicotine withdrawal has the opposite effect. This is one reason why people who quit smoking find that they rapidly gain weight. They’re trying to get their serotonin “fix” from food instead of cigarettes.

The food you eat has the potential to raise or lower your serotonin levels. That’s why the ingredients of a meal have such a powerful impact on the way you feel after you eat it. To understand why, you need to know a little more about an amino acid called tryptophan (pronounced trip-toe-fan), which your body uses to make serotonin.

If you were to eat just tryptophan by itself, then it would enter the blood, flow into the brain, and raise serotonin levels. So if you want to raise your serotonin levels, all you need to do is eat protein-rich foods that are high in tryptophan, right? Not so fast.

Tryptophan requires the use of a transport molecule to cross the blood-brain barrier. Several other amino acids (tyrosine, phenylalanine, valine, leucine and isoleucine) “compete” for this transport molecule. Because whole foods contain other amino acids besides tryptophan, the presence of these competing amino acids can inhibit the transport of tryptophan into your brain. That’s why eating a food high in tryptophan, such as cottage cheese or turkey, is NOT the best way to raise serotonin levels.


Although it might sound counterintuitive at first, it’s actually meals that are high in carbohydrate rather than protein that have the biggest impact on serotonin. Why?

When you eat a food high in carbohydrate, your body releases insulin. Insulin helps to clear the competing amino acids from your blood. However, insulin has no effect on tryptophan. Consequently, once insulin has cleared the competing amino acids from your blood, tryptophan is free to enter your brain.

The link between serotonin and sleep is one reason why some people feel tired after eating a high-carbohydrate meal. It also helps to explain why foods high in carbohydrate are often described as “comfort” food.

Dr. Albert Stunkard, a professor of psychiatry at the University of Pennsylvania, thinks that people with an almost uncontrollable urge to raid the fridge late at night are doing it to help themselves sleep by boosting serotonin levels.

If you’ve ever wondered why diets leave you feeling cranky, low serotonin levels could be the explanation. If you’re a woman, the news gets even worse, as the drop in tryptophan appears to be greater in women than it is in men. Researchers from the University of Oxford, for example, found that just three weeks on a low calorie diet significantly reduced both tryptophan levels and the ratio of tryptophan to competing amino acids in a group of 15 men and women. But despite a similar drop in weight, the decline in tryptophan was greater in the women than it was in the men. This could go a long way towards explaining why dieting seems to cause bigger mood swings in women than it does in men.

Free meals

One solution to the problem of low serotonin levels is to include some kind of high-carbohydrate “free meal” in your diet once or twice a week. The typical way most people go about dieting is to adopt an “all-or-nothing” approach. Maybe this is something you can relate to.

Let’s say that you’ve been following a diet without any kind of lapse for the last few weeks and your progress has started to slow down. There are days when you feel tired, anxious or just a little irritable. To make matters worse, you’re getting cravings for some of the foods you’ve cut out of your diet. Maybe it’s something sweet like chocolate, or savoury like bread. You hold out for days until finally you give in. It might start with one cookie. But it doesn’t stop at one, and you end up eating the whole packet. And that’s it. The diet’s over. You feel like you’ve failed again.

As often happens with the all-or-nothing approach, the end result is usually nothing. A free meal can help you stick to your diet in the long-term because you know you’re never more than a few days away from indulging in a few of your favourite foods.

I much prefer free meals to cheat days, mainly because there’s an upper limit to the amount you can eat in a single sitting.

While some people will impose some kind of limit on what they eat during a cheat day, others will consume anything and everything in sight. Because of this, a single cheat day once each week has the potential to undo much of the good work you’ve done during the previous six days. And if you plan your free meals to coincide with some kind of social occasion, it’s possible to follow a diet and have a life at the same time.

About The Author
Christian Finn holds a master’s degree in exercise science, is a certified personal trainer and has been featured on BBC TV and radio, as well as in Men’s Health, Men’s Fitness, Muscle & Fitness, Fit Pro, Zest and other popular fitness magazines.