How you eat affects virtually every aspect of your health, including the health of your brain. And while a well-designed low-carb plan should supply all the nutrients you need for healthy brain functioning, you've likely heard that lack of carbs decreases your brainpower. That seems to be true for some people, but other evidence suggests that eating low-carb might have a neutral or even positive impact on your brain function.
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Carbohydrates and Your Brain
If you've ever been told to carb-load for a game, race or a tough workout, you know carbs are key for boosting your energy. Your body turns them into glucose, which also directly fuels your brain. Your brain cells can actually only use glucose for energy, which makes carbs absolutely essential for powering brain function.
That's not the only way carbs affect brain function, though. Eating carbohydrates signals for your brain to produce serotonin, a hormone that's involved in mood regulation, appetite control and the sleep cycle. That may be one reason that carbs are considered "comfort food" and why you might crave carb-rich foods when you're upset or stressed.
Can a Low-Carb Diet Diminish Brain Function?
Low-carb diets have a bad reputation for affecting your brain function. And it makes sense -- because your brain needs carbs for energy, lowering your carb intake might affect your brainpower. You might experience fuzziness or "brain fog" if you're not getting enough carbs through your diet or have trouble concentrating due to general fatigue from lack of carbs.
Researchers have looked into this effect in low-carb dieters. One study, from a 2009 issue of Appetite, examined the effects of a low-carb weight-loss diet on brain function in study subjects during their first three weeks on the diet. They found low-carb dieters did worse on memory tests than dieters following an American Dietetic Association diet, which recommends a balance of carbs, protein and fat. Once the low-carb dieters started eating carbs, their memories returned to normal. While this small study looked at just nine low-carb dieters and doesn't mean everyone eating low-carb will see a decrease in brain function, it suggests any "brain fog" you experience isn't all in your head.
Benefits of Low-Carb for Your Brain
While the low-carb brain fog might be a real thing -- at least in some people -- going low-carb may actually benefit your brain function in the long term. Low-carb diets are great for helping you lose weight and may also protect you from type-2 diabetes. That's good for your brain because the insulin resistance that occurs in type-2 diabetes and prediabetes actually lowers your brain function, causing symptoms similar to Alzheimer's, according to a study published in JAMA Neurology in 2001.
There's also some evidence the decrease in brain function doesn't happen for everyone following a low-carb diet. One study, published in Nutrition & Diabetes in 2013, found that low-carb and high-carb diets had roughly the same effects on cognitive function. Another study, from a 2009 issue of the Archives of Internal Medicine, found that people reported better emotional control and moods when they followed a low-carb diet for a year.
Low-Carb Foods for Brain Function
You can eat for brain health even if you're following a very-low-carb diet. Make sure to include salmon, chia seeds, flaxseed and walnuts in your low-carb meal plans. These supply omega-3 fatty acids, nutrients your brain needs to make myelin, an "insulator" that helps your nerves communicate properly. The meats, leafy green veggies, nuts and beans in your diet contribute B-complex vitamins, which help you make myelin as well as produce brain hormones, like serotonin. And protein supplies tryptophan, an amino acid needed for serotonin production.
Including lower-carb fruits, like berries, also boosts brain health. They support communication between your brain cells and brain cell survival, and including them in your diet keeps your brain healthy as you age, reports a review published in the Journal of Agricultural and Food Chemistry in 2012.
- Dartmouth: You Are What You Eat: How Food Affects Your Mood
- University of Washington: Nutrition and the Brain
- Michigan State University: Fueling Your Brain: The Keys to Improving Concentration
- University of Utah: Negative Reactions to Starting a New Diet
- Appetite: Low-Carbohydrate Weight-Loss Diets. Effects on Cognition and Mood
- JAMA Neurology: Insulin Resistance and Alzheimer-like Reductions in Regional Cerebral Glucose Metabolism for Cognitively Normal Adults With Prediabetes or Early Type 2 Diabetes
- Archives of Internal Medicine: Long-Term Effects of a Very Low-Carbohydrate Diet and a Low-Fat Diet on Mood and Cognitive Function
- Nutrition & Diabetes: Similar Effects on Cognitive Performance During High- and Low-Carbohydrate Obesity Treatment
- Arizona State University: Nutrition for Brain Function and Mood Control
- Journal of Agricultural and Food Chemistry: Berry Fruit Enhances Beneficial Signaling in the Brain