Q: Do Humans Get Fatter In The Winter?

Recently one of my clients asked a fantastic question.

Q: Do humans tend to store more fat during Fall and Winter months?

A: Possibly.

Certain uncontrolled studies have shown humans to experience seasonal weight fluctuation, with winter body mass being about .5kg/m2 higher than in summer. According to The Journal of Clinical Endocrinology and Metabolism, a patient-controlled study conducted at the University of Colorado showed that body fat was not affected by season, although cholesterol levels increased between November and February.

However, there are a variety of factors which may influence fat storage during winter months which we may consider.

As days shorten less Vitamin D is available from the sun which in turn decreases serotonin levels and creates a condition commonly referred to as Seasonal Affective Disorder (SAD). Lower serotonin and the accompanying depressive mood can result in "emotional eating", which consists of ingesting larger than normal quantities of carbohydrates in an attempt to anti-depress.

The winter holiday season includes a slew of Western celebrations such as Halloween, Election Day, Black Friday, Hanukkah, Winter Solstice, Christmas, Kwanzaa, New Year's Eve, and Valentine's Day. Holidays are source of stress for many, and emotional stress triggers the production of cortisol, the dreaded steroid hormone manufactured by the adrenal gland which increases blood sugar levels, increases blood pressure, suppresses the immune system, and plays a major role with regard to appetite and obesity.

Testosterone, the "hormone of desire", which is responsible for increased sex drive, muscle gain, and fat loss, rises and falls throughout the year but peaks during summer months with lowest levels occurring during the winter months.

Finally, an enzyme called LPL, or Lipoprotein lipase, promotes fat storage and spikes during the winter months. LPL is what makes it possible for hibernating animals to survive during hibernation. When LPL levels rise, fat storage becomes easier.

Tips to Stay Lean During the Winter:

- Take a Vitamin D supplement daily. I personally recommend Carlson's Vitamin D3 4000IU gels. Also, look into indoor tanning. Contrary to what your dermatologist may tell you, controlled doses of UVA and UVB radiation actually safeguard against sunburn and lower incidence of colon, breast, and prostate cancers. Find a reputable facility, ask about their bulbs, UVA/UVB concentration levels, exposure time, and do some research on your own. Diving in for a few minutes of UVA/UVB exposure each day can have a very positive effect on your health.

- Take a probiotic. There are many brands to choose from, I take OrthoBiotic and Culturelle. Probiotics should be alternated every 1-2 months so that new colonies of flora are circulated. Gut health is total body health.

- Exercise! Find a gym, get an accountability partner or a personal trainer, and hit it. HARD. Moderate to vigorous exercise 5-6 days per week, 1 hour per day, will increase testosterone production, lower cholesterol, boost energy, improve mood, reduce stress, regulate digestion, and balance hormone levels. Workouts which involve conscious breath exercises such as yoga are highly recommended.