Tag Archives: insulin sensitivity

Brown Fat and the Cat in the Hat

My son Paul made this

My son Paul made this (I’ll see you in heaven, Romeo)

The Joslin diabetes blog has an interesting article on brown fat and its effect on metabolic rate and insulin sensitivity. Brown fat is just a type of body type different from the more plentiful white fat (which is actually more pale yellow). If there are other colors of body fat, I don’t know.

If you can “activate” your brown fat, it helps you burn more calories, which could be helpful if you’re trying to lose weight. It also improves insulin sensitivity: beneficial if you have type 2 diabetes or are prone to it.

From Joslin:

“When brown fat is fully activated, it can burn between 200 and 300 extra calories per day. It is most successfully activated through cold exposure. A recent study of people with type 2 diabetes had volunteers sit in a 50 degree room for a couple of hours a day for 10 days in shorts and short-sleeved shirts.

“When I say cold, it’s not icy cold, it’s not like the winter in Boston,” she says. “It’s more or less like the temperature we have here in autumn. After this mild cold exposure, all ten volunteers with type 2 diabetes, as shown in that study, displayed increased brown fat activity and improved insulin sensitivity. This is very exciting.”

Dr. Tseng is working on understanding exactly what is happening on a cellular level to activate brown fat in the cold to see if she can create a drug that will mimic the effects. “Although cold works, it’s just not pleasant,” she says. “If you had to sit in a cold room for a few hours every day, perhaps not everybody could accept that.”

Source: How Your Body Temperature Can Affect Your Metabolism | Speaking of Diabetes | The Joslin Blog

Another way to activate brown fat is exercise (at least if you’re a man or a mouse).

Steve Parker, M.D.

Prolonged Sitting Is the New Trans Fat: Avoid It

Within the last couple months I read somewhere that the adverse health effects of sitting all day long are not counteracted by an hour of vigorous exercise.  If true, that’s disappointing to many of us.

I think this is the research report that got the buzz going.

The investigators suggest you’re better off with four hours of standing and two hours of walking.  Easy peasy, right?

Some caveats.  It’s a very short-term small study of young adults (18 initially but three dropped out).  The “prolonged sitting” regime lasted 14 hours.   The health focus of the study was limited to insulin levels, insulin sensitivity, blood sugar levels, and blood lipids like cholesterol and triglycerides.

Where did I read, “Sitting is the new saturated fat”?

The investigators conclude…

One hour of daily physical exercise cannot compensate the negative effects of inactivity on insulin level and plasma lipids if the rest of the day is spent sitting. Reducing inactivity by increasing the time spent walking/standing is more effective than one hour of physical exercise, when energy expenditure is kept constant.

The Washington Post in July, 2011, had an article along the same lines (h/t Beth Mazur).

—Steve Parker, M.D.

Reference:  Duvivier BMFM, Schaper NC, Bremers MA, van Crombrugge G, Menheere PPCA, et al. (2013) Minimal Intensity Physical Activity (Standing and Walking) of Longer Duration Improves Insulin Action and Plasma Lipids More than Shorter Periods of Moderate to Vigorous Exercise (Cycling) in Sedentary Subjects When Energy Expenditure Is Comparable. PLoS ONE 8(2): e55542. doi:10.1371/journal.pone.0055542