Does excessive weight gain cause insulin-resistance or does insulin-resistance cause excessive weight gain?
It is well known that insulin resistance commonly coexists with obesity.  Dietary fat and high triglyceride counts have long been implicated as a driver of insulin resistance.  Many experts and health professionals strongly believe that being insensitive to insulin is still positively correlated with fat intake, and negatively correlated with dietary fiber intake, but both these factors are also correlated with excess body weight (Lovejoy, 1992).

Insulin-resistance and weight gain/obesity

Insulin resistance (IR) is a physiological condition in which cells fail to respond to the normal actions of the hormone insulin.  The body produces insulin, but a reduction in sensitivity of receptor cells, particularly in the liver and skeletal muscle are unable to use it effectively compared to normal systemic conditions.  Simply put, insulin cannot fulfill its normal duties to function in a homeostatic (balanced) state under any conditions.  As a result, a high level of glucose along with elevated insulin remains circulating in the bloodstream leaving these sugar-starved cells crying for energy. Subsequently, the system will involuntary regulate by sending hunger signals to the brain which can lead to overeating.  And because fat cells tend to retain their sensitivity to insulin, unused glucose from “over fueling” is eventually stored in adipose (fat) tissue leading to weight gain, obesity and increased risk of cardiovascular disease (Lustig, 2005).  Additionally, studies have shown that elevated levels of the stress hormone cortisol in the bloodstream may contribute to these conditions and can increase the risk of type 2 diabetes, although a causative factor is unknown (Aronson, 2009).

In an IR state, clearly the body is systemically distressed and operating in a dysfunctional state when glucose enters the bloodstream.  While a rapid rise and subsequent fall in blood glucose and insulin levels may play a contributing role to unnatural hunger cravings, some experts proclaim that this is merely a condition resulting from systematic overeating causing an eventual increase in adipose tissue from a hypercaloric diet, thus devaluing the theoretical impact of exaggerated levels of sugar and insulin alone as the root cause for excessive weight gain.  Some scholars go as far as to claim that neither insulin resistance, nor obesity really are metabolic disorders per se, but simply adaptive responses to sustained caloric surplus (Unger, 2010).

Bottom line:  Weight gain is attributed to excessive calorie consumption. If you tirelessly consume more energy (calories) than you expend over a period of time you will gain body weight primarily in fat stores regardless of sugar and insulin levels in the blood.  This seems to be the more common consensus among medical professionals and fitness enthusiasts for the existence or onset of the abnormal metabolic conditions previously discussed.

If you are honestly concerned about your current state of health and experiencing levels of fatigue or frequent compulsive eating binges, consult a physician.  These symptoms and/or behaviors may be the result of a myriad of factors including stress and anxiety leading to the existence of an IR state, weight gain and perhaps clinical obesity.  Furthermore, type 2 diabetes or insulin-resistance is treatable and can be managed through a balanced healthy eating plan with appropriate daily calories needed under the supervision of a nutritionist.  This can be complemented with regular physical activity and blood sugar monitoring.  In some cases, diabetes medications and insulin therapy may apply. Strategies for stress management are also highly recommended including better quality sleep, acupuncture, practice of mindfulness and mental relaxation exercises.  In time, these practical methods can return the system back to functioning in a homeostatic state and perhaps reduce those powerful unnatural hunger cravings.