Ever wonder what makes you hungry or crave certain foods? Why you always have enough room for dessert even though you just finished a big meal? Or why you might stand in front of an open fridge full of food and then say, “We have nothing to eat!”? Such is the power of neurotransmitters.
Neurotransmitters – The Basics
The human brain is composed of roughly 86 billion neurons (nerve cells). (1) These nerve cells communicate with each other via chemical messengers called neurotransmitters. There are two types of neurotransmitters: inhibitory and excitatory. While inhibitory neurotransmitters calm the brain, excitatory neurotransmitters stimulate the brain.
Neurotransmitters affect sleep, mood, motivation, memory, focus, energy, libido, weight, and can cause adverse symptoms when they are out of balance. It’s been estimated that 86% of Americans have sub-optimal neurotransmitter levels. Stress, lack of sleep, poor diet, addictive substances, and genetic predisposition are all to blame for poor neurotransmitter levels. (2)
How Do Neurotransmitters Affect Weight Loss?
When most people think of weight loss, they don’t usually think of the brain. The brain, however, has a dramatic impact on body composition. Your appetite is not only a product of your physiology, but also your psychology; it’s a complex interaction of hormones and neurotransmitters.
If you’re curious what the difference between hormones and neurotransmitters is, below is a simplified table that demonstrates it.
So which neurotransmitters are the biggest players in weight management? While all neurotransmitters are important, the big “four” are dopamine, acetylcholine, GABA, serotonin, and melatonin.
Dopamine – The Pleasure Hormone
In terms of weight loss, dopamine is the most important of the four brain chemicals. Dopamine is a unique neurotransmitter in that it can be excitatory or inhibitory, depending on the receptor it binds to. (3) It’s derived from the amino acid tyrosine and is released during gratifying activities, such as food consumption, sex, exercise, and several drugs (4). The function of dopamine is diverse as it plays a role in pleasure/reward, mood, attention, and motor skills.
Those low in dopamine often use foods and stimulants to get them through the day. The problem is that most of the foods and stimulants people crave – chocolate, candy, diet sodas, coffee, or energy drinks – lead to unhealthy eating habits and obesity. (5) Each of these substances actually do boost dopamine production. So in a sense, you are self-medicating correctly, although dangerously. Research shows that dopamine-induced behavior leads to repeated cravings and overindulgence. (6) Without the right amount of dopamine, you’re never physically and emotionally fulfilled by food, no matter how much you’ve eaten. So you keep eating and eating and eating.
While not enough dopamine can leave you fatigued – craving food and stimulation – too much can cause addictive behaviors. Dopamine is one of the reasons why foods can be addictive. Not surprisingly, almost all abusive drugs and addictive substances, such as alcohol, nicotine, cocaine, and even sugar, influence dopamine production.
The goal for weight loss is to have a dopamine signaling system that regulates and balances your body with sustained energy and motivation. Besides the many pleasures dopamine brings, healthy levels of dopamine naturally suppress appetite and aid weight loss. Just be aware that dopamine does decrease with weight loss. (7)
To Positively Influence Dopamine Levels
- Limit your sugar intake: sugar alters brain chemistry by disrupting dopamine levels. That’s why people experience a “sugar-high” shortly after eating sweets. In fact, sugar stimulates the exact same euphoric pathway as alcohol and drugs. (8)
- Supplement with l-tyrosine: since tyrosine is the building block of dopamine (9), supplementing with tyrosine can help increase dopamine production. Even better choice is acetyl-l-tyrosine, which is a more bio-available form.
- Eat foods high in tyrosine: bananas are an exceptional food for regulating dopamine because they have a high concentration of tyrosine. Other foods known to boost dopamine levels include almonds, apples, beets, watermelons, cherries, pumpkin seeds, sesame seeds, yogurt, beans, eggs, fish, and meats. (8, 10)
- Limit caffeine: just like sugar, coffee offers only temporary relief. After experiencing the initial kick caffeine offers, dopamine levels in the body decrease. So, go for a cup of decaf instead. (11)
- Avoid stress and relax: meditation, self-reflection, hot bath, or a massage are all activities that increase dopamine levels. (12)
Acetylcholine – The Memory Hormone
Like dopamine, acetylcholine is one of the brain’s “on” (excitatory) switches. A healthy, high acetylcholine brain is fast-moving and quick-thinking. While the dopamine brain is all about seeking reward, acetylcholine is your key to awareness. Without it, you wouldn’t be able to remember the last time you ate, so you’d eat again and again and again. (13)
Symptoms of acetylcholine deficiency are typical of “senior moments” – struggling to remember, focus, and find the right words. Just as you may reach for sugar and caffeine for that burst of energy to compensate for a dopamine deficiency, you might reach for fatty foods to eat your way into thinking better. An acetylcholine deficiency can make you crave foods high in fat, like those found in greasy fast foods, fried foods, hamburgers, pizza, and creamy desserts. That’s because fat is the main source of choline, the building block of this brain chemical. When you eat foods high in fat, they deliver an instant acetylcholine boost. (14)
While you do need enough fat to keep your acetylcholine levels stable, don’t get carried away eating too much. That’s especially important if you’re trying to lose weight. Foods that are high in fat are not only calorie-dense, but also low in nutrients.
To Positively Influence Acetylcholine Levels
- Eat foods high in choline: eggs are by far the best sources of choline. (15) Other sources include avocados, olive oil, nuts, and seeds.
- Supplement with l-carnitine: acetyl-l-carnitine is an amino acid that enhances the use of fatty acids for energy production and is a brain antioxidant. It is also believed to contribute to the production of acetylcholine in the brain. (16)
- Load up on DMAE: dimethylaminoethanol (DMAE) is an anti-inflammatory and antioxidant that slows down the breakdown of choline in tissues outside of the brain. As a result, more choline is available to be turned into acetylcholine. If you don’t feel like getting a supplement, DMAE is also found in sardines, anchovies, and salmon.
Serotonin – The Happiness Hormone
Off all the neurotransmitters, serotonin gets the most attention. It’s derived from the amino acid tryptophan and belongs to the inhibitory group of relaxing neurotransmitters. Serotonin provides a sense of well-being and happiness. If you wake up in the morning excited to take on new challenges, your serotonin levels are most likely in a healthy range. If, on the other hand, you experience depression, insomnia, and low self-esteem, you might want to give your serotonin some boost.
Serotonin is a natural appetite suppressant and its deficiency is closely related to weight gain. Low serotonin levels cause carbohydrate cravings because tryphtophan – the building block of serotonin – can only get into the brain after sweet or starchy foods are eaten. While tryptophan is found in all protein, so are all the other amino acids tryptophan has to compete with to enter the brain. To tryptophan’s disadvantage, there are more of the other amino acids in the blood that get into the brain faster. (17)
Carbohydrates tip odds in tryptophan’s favor. Carbohydrates stimulate insulin, which pushes nutrients such as amino acids into the cells of the heart, liver and other organs. As it does this, tryptophan stays behind. Now there is more tryptophan in the blood than the competing amino acids and tryptophan gets into the brain. The tryptophan is immediately converted to serotonin, curbing appetite and cravings even if your stomach is not entirely full. The result? Eating less and losing weight. (17, 18)
To Positively Influence Serotonin Levels
- Eat foods rich in carbohydrates after you’ve eaten enough protein: in order to properly synthesize serotonin, you need to have enough tryptophan in the blood => eat enough protein. In order to transport the tryptophan into the brain, you need to stimulate insulin production => eat enough carbohydrates. While simple and refined carbohydrates raise serotonin levels the quickest, they aren’t a good long-term strategy for overall health. With complex carbohydrates, which break down slowly in the body, the serotonin increase isn’t as dramatic as with simple carbohydrates. However, the serotonin elevation is more consistent and longer-lasting.
- Supplement with tryptophan and B vitamins: to increase serotonin tryptophan supplements work better than tryptophan found in food. B vitamins are another important precursor regarding serotonin production. Vitamins B1, B3, B6, and B9 all help convert tryptophan into serotonin.
- Enjoy the sunlight: sunlight is one of the best sources of vitamin D, which plays a key role in the synthesis of serotonin. Although vitamin D supplementation can be beneficial, it isn’t nearly as beneficial as obtaining vitamin D from direct sunlight. Studies show that serotonin synthesis increases based on the number of sunlight hours, regardless of the season. (19)
- Get enough sleep: it is believed that lack of sleep disrupts optimal neurotransmission of serotonin. (20). Moreover, the disruption that occurs as a result of sleep restriction for over a week persists for days, even with “unlimited” recovery sleep. To reverse the disruption in the brain’s serotonin system, you’d need to get proper sleep for approximately a week. (21)
- Exercise regularly: many medical professionals recommend aerobic exercise for mood improvement. It is believed that exercise also increases the availability of tryptophan, which is converted into serotonin. (22)
GABA – The Calming Hormone
Gamma-aminobutyric acid (GABA) functions as your brain’s calming agent. It’s the chief inhibitory neurotransmitter. Along with serotonin, it creates a sense of calm and order, what Dr. Eric Braverman calls the “Zen” of the brain. (13) Optimal levels of GABA leads to a reduction in stress, anxiety, nervousness, and improvement in sleep. (23, 24, 25) Typical symptoms of low GABA are being easily stressed out, over-stimulated, and overwhelmed.
In order to lose weight, you need to have a calm, stable brain chemistry supported by exactly the right amount of GABA. GABA can aid sleep, improve mood, and prevent psychological causes of overeating. Those with GABA deficiency tend to eat way too much and way too fast to counteract the stress and anxiety in their lives. They use food to soothe their mind.
To positively influence GABA levels:
- Choose GABA-producing foods: the goal of a high-GABA diet is to ensure that the body has enough glutamine, the amino acid precursor to GABA. Glutamine is found in raw, leafy vegetables, cabbage, beans, and animal-protein foods.
- Eat fermented foods: unpasteurized yogurt, kefir, saurkraut, kimchi, and miso all positively influence GABA. Probiotic supplements also markedly improve GABA levels. (26)
- Supplement, but not with GABA: while GABA supplements are available, they are not ideal because the GABA molecule is too large to cross from the blood into the brain. A good supplement to try instead is amino acid taurine, which activates GABA receptors in the brain and encourages the formation of GABA. (27) Other GABA-boosting supplements include magnesium, kava, inositol, and theanine. (13)
- Exercise regularly: while any exercise is beneficial, yoga especially increases GABA levels. (28)