How Low-Carb Diets Hurt Your Mood

More than a decade's worth of studies from Massachusetts Institute of Technology, in Boston, revealed that serotonin, the brain's mood-lifting neurotransmitter, is affected by food, and it turns out that eating carbohydrates, not protein, boosts serotonin production. Carb deprivation can therefore dampen your mood, making you impatient and grumpy, says Judith Wurtman, PhD, director of the Program in Women's Health at the MIT Clinical Research Center. "It's not going to put you into a full-blown depression, but it can put you on edge," she says.

But much like the low-carb diet itself, scientists disagree on the low-mood theory. Pro-carb-cutters blame mood swings on carb-induced spikes in insulin levels rather than plummeting serotonin. One study, published in the New England Journal of Medicine, compared weight loss in low-carb and low-fat dieters, but didn't find a difference in the mood of either group. But a British study from Oxford University of 42 women on low-carb diets found that those with a history of depression experienced a "striking but temporary relapse in symptoms." While the jury is out, you might want to keep a rice cake on hand if you're going low carb and are prone to low moods.

Originally published in Ladies' Home Journal magazine, June 2004.