When it comes to obesity, inflammation and weight gain form a vicious cycle. Either can get the ball rolling and have an overlapping influence, further propelling metabolism toward derangement and increasing weight gain.
The basic mechanism underlying this vicious cycle begins with some degree of initial weight gain. It may start with chronic stress, sleep deprivation, and a mix of stimulants and sweets to help you cope. Those few extra pounds then change the way your metabolism functions. Fat cells, known as adipocytes, swell in size causing cellular stress and a decrease in oxygen to themselves. This deprivation can lead to the adipocytes’ untimely demise as well as a release of pro-inflammatory chemicals known as cytokines.
The death of these cells triggers your immune system to come clean up the debris. Special cells known as macrophages arrive to help, but as the cycle worsens, the immune system responds in greater proportion, further ramping up the release of inflammatory mediators resulting in a localized insulin resistance in adipocytes as well as the liver. Gone unchecked, the amassing inflammation within these cells dovetails into systemic insulin resistance, the hallmark of type II diabetes.
If increased weight gain from inflammation was not bad enough, inflammatory cytokines also induce an enzyme processes called aromatization which is responsible for the conversion of androgen hormones into estrogens, particularly into proinflammatory and proliferative estrogens. This is a fancy way of saying that inflammation can be a dominant driver of estrogen dominance, and estrogen-linked cancers. This poses an additional challenge for women trying to lose weight in a climate of high estrogen.
Of course, inflammation and insulin resistance can occur without weight gain. There, stress may be the primary culprit, feeding inflammation like fuel on a fire. Obesity is simply another contributor, albeit a very potent one, and if you are already predisposed to weight gain due to diet, lifestyle, and genetics, increasing weight gain can ensue.
Besides stress, another factor linking inflammation and insulin resistance/weight gain is the ingestion of trans-fats common in highly-processed and hydrogenated vegetable oils. In one study, a 2% increase in trans-fat consumption correlated with a forty percent increase in insulin resistance and type II diabetes. Distorted oxidized fats such as trans-fats are inherently pro-inflammatory, disrupting an enzyme system in the body responsible for the normal utilization of fats, including the burning of fat stores for energy.
Refined carbohydrate consumption can be inflammatory in its own right, but its effect on metabolism contributes to weight gain. Besides creating an insulin spike that can lead to insulin resistance over time, the increased need for glucocorticoid hormones, such as cortisol, have a direct action on fat cells, stimulating fat cell division.
The take home message is to consider inflammation as a fundamental cause and result of weight gain. Inflammation can create a vicious cycle, exacerbating and accelerating weight gain.