In trying to lose 20 pounds, my friend began a low-carbohydrate diet because she claimed that her weight gain was caused by her love for carbohydrates.  Three weeks into the diet she began to feel irritable and at times depressed.  She called to ask me if this was a typical response to low-carb dieting, not knowing whether the diet was causing her mood swings or if it was something else.  What has made low-carb diets so popular, how do they work, and can they affect your mood?

After realizing that not all fats are bad, as once thought in the 1970s and 1980s, new research suggested that a carbohydrate-controlled approach to dieting was more effective for weight loss than low-fat diets.  It is estimated that there are currently 30 million people in the U.S. following some sort of diet that restricts carbohydrate intake.  There are over 200 low-carb specialty retailer locations, low-carb cooking shows, and many low-carb diet programs such as Atkins and South Beach.  There are even low-carb specific magazines such as Low Carb Living. 

Low-carb diets call for participants to restrict their carb intake so that their body burns more glycogen (stored carbohydrates) for energy.  Super low-carb diets can even force the body to burn fat and protein instead of carbohydrates by using a metabolic process called ketosis.  Many low-carb dieters follow a basic, but flawed, philosophy - they cut down on carbohydrates, but they make up calories by consuming more than typical amounts of fat and protein.  Most health experts agree that the excessive intake of protein and fat can cause undesirable effects such as an abundance of ketones, a by-product from ketosis, which in turn can cause symptoms such as nausea, fatigue and bad breath, or even kidney failure and gout, and can increase risk of osteoporosis and kidney stones, according to the Cleveland Clinic. 


Low-carb dieters are also susceptible to mood swings, according to researchers at the Massachusetts Institute of Technology Clinical Research Center (MIT) in Boston.  Studies on rats have shown a connection between a diet low in carbohydrates and low levels of serotonin's neurotransmitter that promotes feelings of happiness and satisfaction.  Rats placed on a low-carb diet for three weeks had lower levels of serotonin in their brains.  Researchers believe the same effect occurs in humans on low-carb diets and leads to pronounced feelings of depression.


However, not everyone experiences differences in mood when on a low-carb diet.  Some people may not see a difference in their attitude because their bodies may digest carbohydrate at a steadier rate, or they may have naturally higher levels of serotonin in their brains.  Because of her research at MIT, Dr. Judith J. Wurtman believes that low-carb diets may not be the diet choice for individuals who are already struggling with depression or bipolar disorder.


So should you drop that low-carbohydrate diet?  It depends on how you feel--if you notice a drop in energy or mood that affects daily performance while on a low-carb diet, try a new diet.  A more moderate approach to losing weight is to choose a diet with an appropriate amount of calories for weight loss that includes complex carbohydrates and lean proteins and is plentiful in fruits and vegetables. 

Alice Burron is an affiliate spokesperson and highly successful personal trainer for the American Council on Exercise.  She earned a master’s in physical education with an emphasis in exercise physiology from the University of Wyoming and is a leading national fitness and wellness program expert.    

Check out Alice's new book Four Weeks to Fabulous, created to empower the average working woman who is busy with her family, career, and wants to take control of her weight - and health.  Four Weeks to Fabulous is available at, or can be purchased on Amazon.  Please note that when ordering on, you must click on Buy Now under "Special Offer for NurseTogether members - Free Shipping."  

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