T Nation

insulin resistance and fat storage

With all the talk of insulin resistance lately I decided to post this. I have often noticed as men age many of them get a much bigger gut without any increase in subcutaneous fat. Now I know why. Have a look at this.


Insulin Resistance in Lean and Fat Subjects

Do lean insulin-resistant subjects have similar body fat distribution
compared with obese Insulin Resistant individuals? This article examines
this issue.


The Concurrent Accumulation of Intra-Abdominal and Subcutaneous Fat Explains
the Association Between Insulin Resistance and Plasma Leptin Concentrations

Diabetes 51(4):1005-1015, 2002

M Cnop, MJ. Landchild, J Vidal, NG Knowles, Feng Wang et al

Abstract

Obesity is associated with insulin resistance, particularly when body fat has
a central distribution. However, insulin resistance also frequently occurs in
apparently lean individuals. It has been proposed that these lean
insulin-resistant individuals have greater amounts of body fat than lean
insulin-sensitive subjects. Alternatively, their body fat distribution may be
different. Obesity is associated with elevated plasma leptin levels, but some
studies have suggested that insulin sensitivity is an additional determinant
of circulating leptin concentrations.

To examine how body fat distribution contributes to insulin sensitivity and
how these variables are related to leptin levels, we studied 174 individuals
(73 men, 101 women), a priori classified as lean insulin-sensitive (LIS, n =
56), lean insulin-resistant (LIR, n = 61), and obese insulin-resistant (OIR,
n = 57) based on their BMI and insulin sensitivity index (SI). Whereas the
BMI of the two lean groups did not differ, the SI of the LIR subjects was
less than half that of the LIS group. The subcutaneous and intra-abdominal
fat areas, determined by computed tomography, were 45 and 70% greater in the
LIR subjects and 2.5- and 3-fold greater in the OIR group, as compared with
the LIS group. Fasting plasma leptin levels were moderately increased in LIR
subjects (10.8 ± 7.1 vs. 8.1± 6.4 ng/ml in LIS subjects) and doubled in OIR
subjects (21.9 ± 15.5 ng/ml). Because of the confounding effect of body fat,
we examined the relationships between adiposity, insulin sensitivity, and
leptin concentrations by multiple regression analysis.

Intra-abdominal fat was the best variable predicting insulin sensitivity in
both genders and explained 54% of the variance in SI. This inverse
relationship was nonlinear (r = -0.688). On the other hand, in both genders,
fasting leptin levels were strongly associated with subcutaneous fat area (r
= 0.760) but not with intra-abdominal fat. In line with these analyses, when
LIS and LIR subjects were matched for subcutaneous fat area, age, and gender,
they had similar leptin levels, whereas their intra-abdominal fat and insulin
sensitivity remained different.

Thus, accumulation of intra-abdominal fat correlates with insulin resistance,
whereas subcutaneous fat deposition correlates with circulating leptin
levels.

We conclude that the concurrent increase in these two metabolically distinct
fat compartments is a major explanation for the association between insulin
resistance and elevated circulating leptin concentrations in lean and obese
subjects

So in other words, excess caffeine consumption might give you a big gut as well :slight_smile:

Interesting deduction, very interesting as it makes sense, yet so many of us use caffine in an effort to drop fat. Now I wonder, does ephedrine also cause insulin resistance?

Kelly, this study is very interesting, as we know that stress also leads to abdominal fat. Part of the effect is from cortisol but it could also be from stress induced epinephrine release which decreases insulin sensitivity similar to caffeine induced epinephrine release. Unfortunately ephedrine would most likely induce insulin resistance through this mechanism as will.

In the “JB smackdown of caffeine” thread, I
just wrote a bunch of stuff, including
a study referance, on how stress and epi
make insulin resistance worse. Check it out
there, as I don’t feel like re-writing it.