Why do people who are overweight tend to stay hot when thinner folks are cold?

Fat acts as insulation. Perhaps it’s also because thinner people would have a higher surface area to volume ratio.

Larger people do have more fat and muscle to insulate them, and their bodies work harder (thus creating heat) to maintain themselves. Smaller people have less insulation.

It’s the built-in blubber layer (says the fat guy).

phoenyx is right, thinner people with longer limbs lose heat to the environment faster than stockier people. It has a lot to do with surface area to volume ratios (Allen’s rule and Bergmann’s rule), as well as extra insulation from fat.

I’ve also noticed guys tend to be hotter than woman of the same size. I think that must be a metabolism thing, because guys on average have less body fat than women.

more fat equals more heat insulation.

There are times, remember, when many thin women get very hot, sweaty and red-faced. If you are one of these, dancing nude in the snow is very pleasant…otherwise not so.

My uncle has diabetes and is overweight. He never feels the cold and wears shorts outside in the middle of winter. I think there is a connection between diabetes and body temperature, but I’m not sure how.

Yes, there is a link between diabetes and an increase in blood pressure. The hypertension can then lead to peripheral vascular disease – this essentially is a hardening of the arteries in the legs and feet. This is why sometimes diabetics have to have lower extremities cut off surgically. So it may not be an issue of an overweight diabetic not feeling cold because of extra insulation, but a matter of not being able to feel a change in temperature in the legs and feet.

fat provides insulation and protection. obesity is a HUGE problem for not just the USA/Canada but the world. the health problems are staggering. and people can be overweight not JUST for eating the wrong things. genetics and even some diseases cause people to gain weight. however it is very difficult to lose weight (especially living in the modern world we do with easy access to the most non nutritional food in history).

whales carry up to 35% fat as insulation against cold, and the body fat composition
of animals declines from the cold poles to the equator
http://www.arthurdevany.com/webstuff/WhyWeGetFat.pdf

Let’s make this simple. Body fat comes in two forms: essential and non-essential. The essential fat is necessary for everyone. We all need a certain amount of fat to insulate our organs, control body temperature, and provide a source for energy storage.
Non-essential fat is the leftovers of the good fat. It’s the “I have too much insulation around my organs,” “Look at my spare tire!” and “Is it hot in here or is it just me?” stuff. If that describes you, then head over here to get started with Melt the Fat.
http://www.strength-training-woman.com/body-fat-percentage.html

With no body fat for insulation, the anorectic has difficulty staying warm.
http://www.scienceclarified.com/Di-El/Eating-Disorders.html

Obesity is a chronic disease that affects millions of people around the world. When going back to our primal roots and the origins of the human race, everyone needed a certain amount of fat to store energy and insulate the body. As we have evolved and become more sophisticated we no longer need that same amount of fat for storage and warmth. Also, in our advancing technological revolution, we have become more sedentary.
http://groups.msn.com/ObesityFriendly

Everyone’s inner temperature cycles around a slightly different genetically determined version of 98.6 set by the hypothalamus, the brain region that serves as thermostat. We run a little cooler in the morning, a little warmer in the late afternoon
As for obesity, it is complicated, Dr. Crandall said. Fat may insulate the interior from very hot external temperatures, but it also may compromise heat transfer from interior to skin. Carrying more weight generates more metabolic heat to get rid of. That means more sweat, but research suggests that large people cannot grow more sweat glands to cope with the extra heat load. Radiation of heat from skin to air may become especially important in their heat control.
http://www.nytimes.com/2007/08/14/health/14swea.html?_r=1&oref=slogin

BMI Obesity Classification
0 < 25 Normal
25 < 27 Overweight
27 < 30 Mild Obesity
30 < 35 Moderate Obesity
35 < 40 Severe Obesity
40 < 50 Morbid Obesity
50 < 60 Super Obesity

BMI < 18.5: Underweight
BMI = 18.5 – 25: Normal weight
BMI = 25–30: Overweight
BMI = 30–35: Obesity class I
BMI = 35–40: Obesity class II
BMI > 40: Obesity class III
http://genpharm.dk/page/page.php?lang=2&page=5&tid=14&sid=

People who are morbidly obese are at a much higher risk (compared to individuals who are not overweight) of the following:
premature death
developing diabetes, high blood pressure and heart disease
developing colon, breast, and uterine cancer
developing premature arthritis and joint pain, causing limited mobility and activity.
developing sleep apnea and pulmonary hypertension (which leads to heart failure).

It is estimated that over 400,000 people a year in the U.S. die of causes directly attributable to obesity
http://www.obesityresource.com/obesity-related-health-consequences-diagnosis.php#bmi

In the meantime, the research continues into biochemical reactions in “brown fat,” a kind of tissue that produces heat when an animal is chilled. In people, brown fat is plentiful in infancy but little survives past the age of five. “White fat” makes up the significant portion of body fat, but doesn’t produce heat.
http://www.washington.edu/alumni/columns/sept97/fat3.html

On a plane flight back to NYC from a recent vacation, I read Greg Critser’s “Fat Land: How Americans Became the Fattest People in the World.” Strangely, it was on another recent plane flight back to NYC that I read Eric Schlosser’s “Fast Food Nation,” which I blogged about here and here. Why do I read books about fast food and fat when returning via airplane to NYC? The only reason I can think of is that, when I’m outside NYC, I’m so struck by the fast-food-and-fat thing that I have no choice but to, er, digest my impressions on the way back home.
http://www.2blowhards.com/archives/2006/07/more_fat.html