If the holidays are getting you down about now, what you’re eating could be part of the problem. The common ingredient in most holiday foods — sugar — could be bringing on the blues, suggests a new study.

Not only are there fewer hours of sunlight this time of the year in the Northern Hemisphere, the lack of sun can affect our sleep patterns and contribute to seasonal affective disorder, a form of depression. This is likely to prompt us to eat more sweets in an effort to cheer ourselves up.

Inflammation was found to be the most important physiological effect of added sugars related to mental health.

Taken together, these seasonal conditions can create a perfect storm for the onset of the depression this time of year, according to researchers at the University of Kansas. They found that if we also eat a lot of cookies, cakes, other carbohydrates and sugary foods they trigger metabolic, inflammatory and neurobiological processes linked to depression.

Craving sugar is a common characteristic of holiday or winter-onset depression, according to researcher Stephen Ilardi. Thirty percent of people experience at least some symptoms of winter-onset depression, which could cause them to eat more sweets.

“When we consume sweets, they act like a drug,” explained Ilardi, in a statement. “They have an immediate mood-elevating effect, but in high doses they can also have a paradoxical, pernicious longer-term consequence of making mood worse, reducing well-being, elevating inflammation and causing weight gain.”

The team of clinical psychologists analyzed several previous studies on the physiological and psychological effects of eating sugary foods, using diet information gleaned from the Women’s Health Initiative Observational Study, the NIH-AARP Diet and Health Study, and several other studies.

It is the holiday season, so decide ahead of time which sweets say celebration most to you, and then treat yourself to small portions.

Inflammation was the most important physiological effect of added sugars related to mental health. Depression is a disease of systemic inflammation for about half of people who suffer from it.

Eating high levels of sugar is much like drinking too much alcohol, according to Ilardi. Both are empty calories and toxic at high doses. People with depression should eat a plant-based diet that is high in omega-3 fatty acids to provide all the nutrients a healthy brain needs and, for the most part, avoid both alcohol and sugar.

Here are some tips for getting through the rest of the holiday season and limiting sweets:

  • Eat a healthy snack and drink a lot of water before you go to a holiday party to help control your appetite and resist overindulging in sweets.
  • Bring your own food to parties and family gatherings. Consider deviled eggs, cheese balls, spiced nuts, olives, a fruit or veggie tray.
  • Avoid fruity alcoholic beverages, and have a glass of wine instead.
  • Try not to keep sweets in your house. Send them home with company.
  • It is the holiday season, so decide ahead of time which sweets say celebration most to you, and then treat yourself to very small portions.
  • Women should eat no more than 25 grams of added sugar per day — the equivalent of six teaspoons, according to American Heart Association recommendations. For men the number is 38 grams or nine teaspoons a day. The Dietary Guidelines for Americans suggest that no more than 10 percent of your daily calories should come from added sugars. For a person eating 2,000 calories a day that is about 50 grams or 12 teaspoons.

    Either way, since one can of soda contains eight teaspoons of sugar, it’s probably far less than most of us are eating daily over the holidays.

    The study is published in Medical Hypotheses.