It is well known from epidemiological studies that about 30 percent of obese individuals and 50 percent of overweight individuals are relatively healthy in terms of cardiometabolic risk factors1. The same study also indicated that about 25 percent of normal-weight individuals have significant cardiometabolic risk. A follow-up study indicated individuals defined as “metabolically healthy obese” are not at any long-term risk of heart disease2.
Is the world turning upside down?
I explained the reasons behind these paradoxical observations3 in my book, Toxic Fat. It simply depends on what type of fat cells you have. If you have healthy fat cells (“good” fat), they will pull excess arachidionic acid out of the bloodstream and store it in the fat cells. This buried arachidonic acid can spread inflammation to other organs that ultimately results in the appearance of cardiometabolic risk factors. On the other hand, if you have “bad” fat (unhealthy or sick fat cells), they are not very effective in removing arachidonic acid from the bloodstream. Once this happens, circulating arachidonic acid can metastasize like a cancer to other organs. This begins a very slippery slope toward the early development of cardiometabolic diseases, such as diabetes and heart disease. Finally, you get to the stage of dying fat cells that are surrounded by inflammatory macrophages. Now you are in true trouble as the previously stored arachidonic acid is more rapidly released back into the bloodstream.
Now let's fast forward to a new article in the Journal of the American College of Cardiology4 that simply confirms what I wrote about fat cell inflammation three years ago. As with the earlier epidemiological study, researchers found that about 30 percent of the obese subjects had little inflammation in their fat cells as indicated by the absence of inflammatory macrophages. This percentage of obese patients was essentially identical to that found in the earlier epidemiological study1. When the arterial blood flow of the metabolically healthy obese was compared to lean subjects, the rates were virtually identical, whereas the arterial blood flow rates were much lower (that's bad) in the obese subjects who had significant fat cell inflammation.
Unfortunately, their characterization of inflamed fat cells was incorrect. What they were really looking at was dying fat cells. The fat cells of these so-called metabolically healthy obese subjects were already sick (i.e., bad fat) since there were metabolic markers (hyperinsulinemia, increased TG/HDL ratios, elevated blood glucose and increased CRP levels) that indicated that inflammation was already spreading to other organs (such as the liver, muscles and pancreas).
The best way to know if you have truly healthy fat cells (no matter how many you have) is to have a low AA/EPA ratio in the blood. This remains the best clinical marker of the true health of the adipose tissue. If you have healthy fat cells (good fat), then you can expect cellular inflammation in other organs will be reduced leading to a longer and better life no matter what your weight.
- Wildman RP, Muntner P, Reynolds K, McGinn AP, Rajpathak S, Wylie-Rosett J, and Sowers MR. “The obese without cardiometabolic risk factor clustering and the normal weight with cardiometabolic risk factor clustering: prevalence and correlates of 2 phenotypes among the US population.” (NHANES 1999-2004) Arch Intern Med 168: 1617-1624 (2008).
- Wildman RP. “Healthy obesity.” Curr Opin Clin Nutr Metab Care 12: 438-443 (2009).
- Sears B. “Toxic Fat.” Thomas Nelson. Nashville, TN (2008).
- Farb MG, Bigornia S, Mott M, Tanriverdi K, Morin KM, Freedman JE, Joseph L, Hess DT, Apovian CM, Vita JA, and Gokce N. “Reduced adipose tissue inflammation represents an intermediate cardiometabolic phenotype in obesity.” J Am Coll Cardiol 58: 232-237 (2011).