Understanding Causes of Obesity

I attended a networking event this past weekend and I had the pleasure of meeting a young physical trainer aspiring to expand his personal fitness brand. I questioned him on his experience with training clients over 300 lbs and he was honest to state that he had never trained anyone this size. He then went on to say, “at that weight it’s all about diet, so I would cut down their calories and tell them to walk for 40 minutes a day”. I smiled and shook his hand to continue through the crowd of attendees but his statement stuck with me for hours and not in a positive way. I certainly understand his approach, perhaps he was thinking that in order to maintain a 300 lb frame the caloric intake would need to be approximately 4200 calories so reduce calories and increase energy expenditure and voila, we get weight loss. The approach is simplistic and works in some individuals but does not account for basal metabolism, hormone balance, or fat regulation. I would caution applying the calorie and exercise equation to a client without more depth, specificity, or validity. We have all witnessed the individual who is working out excessively and eating a restricted diet to only gain or merely maintain weight. Oftentimes these individuals are blamed for cheating on their diet but the truth is, their weight loss plan may just not work for their sub-type of obesity.

Excess calories and a sedentary lifestyle can certainly lead to excess weight but they are not the only causes for weight gain.

There are over 50 varieties of obesity!

My discussion with this gentleman lead me to write this post and share the various types and causes of obesity. The list below is derived from lectures, presentations, and published articles quoting my adopted mentor Dr. Lee Kaplan, MD, PhD and Medical Director of the Massachusetts General Hospital Weight Center Program. I remember the first time that I heard Dr. Kaplan speak, I was in the last weeks of my internal medicine residency in Charlotte, NC and he was explaining the intricate pathways involved in obesity and the disease of obesity. I was fascinated. In all of my medical training I had never heard anyone explain the complexity of weight in this way. It revolutionized the way that I practice weight management and taught me that obesity is so much more than just diet and exercise alone.

Types of Obesity

Genetic/Congenital and Syndromic Receptor or Hormone Deficiency Neurologic Metabolic Lifestyle Related or Induced Other
-Prader-Willi Sydrome


-Bardet Biedl Syndrome

-Fragile X

-Cohen Syndrome

-Carpenter Syndrome

-Albright Osteodystrophy

-Alstrom Syndrome

-BFL Syndrome

-Ayazzi Syndrome

-MOMO Syndrome

-Rubenstein-Taybi Syndrome

-Leptin Hormone Deficiency

-Leptin Receptor Deficiency

-POMC Deficiency

-MC4R Deficiency

-Alpha-MSH Deficiency

-Sim-1 Deficiency

-PC-1 Deficiency

-KSR2 Deficiency

-MRAP2 Deficiency

-SH2B1 Deficiency

-BDNF Deficiency

-trkB Deficiency

-Central -Hypothalamic



-Healthy Metabolic

-Thermogenesis Deficient


-Insulin Induced


-Progesterone Induced

-Psychotropic Induced

-Antibiotic Induced

-Endocrine Disorder Cushings, Diabetes

-Endocrine Disruptor




-Early Childhood


-Diet Dependent

-Exercise Sensitive

-Sleep Sensitive

-Phentermine responsive

-Lorcaserin responsive

-Topiramate responsive


-Bupropion responsive

-GLP-1 responsive

-Bypass surgery responsive

-Bypass surgery resistant

-Gastric band responsive

-Viral Adenovirus

-Peripheral related


Adapted from Presentations by Lee Kaplan, MD, PHD and publication Your Weight Matters, Fall 2016

Chart and Classification is Original ContentCopyright 2017 © Melody Covington MD, Abundant Health & Vitality Inc

Diet and exercise will always be the foundation for weight loss. We are learning so much about obesity and how to treat it. It is time to reject the notion that diet and exercise alone are the cure for excess weight. It is also time to stop overestimating the impact of exercise, it is much more essential for weight maintenance than weight loss. As listed in the chart above diet and exercise are not the only causes of obesity, so it can also no longer be our only treatment.