The emerging theory of why obesity is associated with disease risk suggests that it is not the excess amount of fat that results in problems – but rather, it is the inability of the fat tissue (specifically subcutaneous, or under the skin fat) to expand enough to store all the excess calories being ingested. In other words, if obese and metabolically unhealthy individuals could somehow develop more subcutaneous fat tissue, they could theoretically become healthier.
That’s right – get fatter and yet healthier.
While these notions surely seem like heresy or simply void of logic to many of you reading, a study just published ahead of print in the journal Obesity, beautifully illustrates the theoretical argument I just described.
In the study, 12 overweight or obese and metabolically unhealthy subjects were given a drug (Pioglitazone) for a duration of 12 weeks. While the exact actions of this drug, and more generally the thiazolidinediones (TZD) class of drugs are beyond the scope of this post, it is important to understand that these drugs seem to upregulate the production of healthy new fat cells (a process known as adipogenesis) – that is they make you fatter. By doing so, these drugs increase the storage capacity of your fat tissue – something that is limited in unhealthy obese individuals.
And that is precisely what happened in these subjects following 3 months of Pioglitizone administration. First, they gained about 2kg of body weight. Their amount of subcutaneous fat in the belly went up by about 10% and that in their butt/thigh by about 24%. Interestingly, their amount of dangerous visceral fat decreased by about 11%. (Some suggest that visceral fat really begins to accumulate and potentially lead to metabolic problems when benign subcutaneous fat runs out of storage space. Thus, not surprising to see an increase in storage capacity of subcutaneous fat and yet a reduction in visceral accumulation).
Also, a fat biopsy from the belly of the subjects showed that the increase in fat mass was due to an increase in the number of small and healthy adipocytes (fat cells) which are better able to take up more circulating fat.
Alright, so people with excess fat and metabolic problems took drugs for 12 weeks which apparently made them fatter, and what happened to their insulin sensitivity (a major metabolic marker of diabetes risk)?
Their insulin sensitivity improved by over 28%!
That’s right – they got fatter and yet healthier.
Interestingly, the authors were able to show a close correlation between the relative increase in new subcutaneous fat cells and insulin sensitivity – the more new fat cells a subject developed, the more their insulin sensitivity improved.
Still believe the “fat is bad” mantra? As this study illustrates, matters related to excess fat and health risk are much more nuanced than what many would have you believe.
McLaughlin, T., Liu, T., Yee, G., Abbasi, F., Lamendola, C., Reaven, G., Tsao, P., Cushman, S., & Sherman, A. (2009). Pioglitazone Increases the Proportion of Small Cells in Human Abdominal Subcutaneous Adipose Tissue Obesity DOI: 10.1038/oby.2009.380
This post was originally published on Obesitypanacea.com on November 16, 2009.