Shooting for some winter weight loss? If you’re tough enough, try this interesting way to burn more calories with the same amount of work. Not for pansies. Check it out:

A substantial amount of research over the last few decades has documented the significance of “brown fat” (as opposed white fat) for creating extra heat. Initially it was thought to only exist in babies, but has since been shown to exist in the majority of adults as well, to varying degrees. Brown fat generates heat by metabolizing or “cannibalizing” fat.

The kicker is that in order to get it to work, you need to be in the cold. How cold? That needs to be studied further, but studies showed increasing brown fat activity as exposure to cold was also increased.

More research needs to be done in order to make specific recommendations for metabolic purposes.

Obviously, use common sense. If it’s really cold, wear something warm on your hands and feet. Stay fairly close to somewhere you can step into to get warm in case you need to. If it’s close to freezing outside, I would recommend starting out with something like a 10 minute jog and working your way up.

As an added bonus, you’ll get fair dose of Vitamin D (assuming you’re outside) which is very often deficient in Americans and linked to many common chronic diseases. One study of almost 5000 people showed that 41% of US adults were deficient in Vitamin D, with much higher rates in African Americans and Hispanics (82% and 69%, respectively). A lot of us stay cooped up inside most of the winter, so getting out and getting some sun is probably a good idea.

As a general recommendation, you only need 5-20 minutes of direct sunlight on exposed skin, several times per week in order counter Vitamin D deficiency.

Good luck out there!

STUDIES/SOURCES:

Irisin and FGF21 Are Cold-Induced Endocrine Activators of Brown Fat Function in Humans: http://www.sciencedirect.com/science/article/pii/S1550413114000060

Highlights
• Shivering stimulates irisin secretion in humans

• Nonshivering cold exposure increases FGF21, which may be a brown adipokine

• Irisin and/or FGF21 upregulates brown-fat-like program in human adipocytes

• Exercise may be a shivering mimic exemplifying muscle-fat thermogenic crosstalk

A critical appraisal of the prevalence and metabolic significance of brown adipose tissue in adult humans
http://www.physiology.org/doi/abs/10.1152/ajpendo.00298.2010

“We conclude that BAT is present in the majority of adult humans. Presence of BAT correlates negatively with body mass index and glucose concentration. BAT may play an important role in energy homeostasis in adults.”

Brown adipose tissue oxidative metabolism contributes to energy expenditure during acute cold exposure in humans
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3266793/

Recruited brown adipose tissue as an antiobesity agent in humans

“Acute cold exposure at 19°C (66F) for 2 hours increased energy expenditure”

Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease (Vitamin D Recommendations):
http://ajcn.nutrition.org/content/80/6/1678S.short

Prevalence and correlates of vitamin D deficiency in US adults:

http://www.sciencedirect.com/science/article/pii/S0271531710002599