Can a metabolic imbalance prevent weight loss?

Patients' claims that they must have a metabolic imbalance because they continue to gain weight despite eating very little is often met with skepticism if not out-right ridicule. I have found that such claims are not exaggerated, as most obese patients who have difficulty losing weight do have reduced metabolism (reduced number of calories burned per day) and usually have leptin resistance or low tissue thyroid levels (not detected by standard blood tests) that make it very difficult to lose weight.

This phenomenon has been documented in the medical literature as well but has largely been ignored by most physicians. One example is a study by Dr. Rudolph L. Leibel published in the journal Metabolism entitled Diminished Energy Requirements in Reduced-Obese Patients which compared the basal metabolic rate in individuals who had lost significant weight to those of the same weight who had not lost significant weight in the past. The authors found that those who had dieted and lost weight in the past had, on average, a 25% lower metabolism than the control patients who had not lost significant weight.