Medical Compass: Metabolically healthy obesity — Is this a good ‘thing’?

Obesity still increases risks of many chronic diseases

By David Dunaief, M.D.

Have we entered a fourth dimension where it’s possible to be obese and healthy? Hold on to your seats for this wild ride. This would be a big relief, since more than one-third of Americans are obese, another third are overweight and the numbers are on the rise (1). In one analysis referenced by the Centers for Disease Control and Prevention (CDC), the average medical cost for obesity alone is 41.5 percent higher than for those of normal weight, based on 2006 numbers (2). Still, there are several studies that suggest it’s possible to be metabolically healthy and still be obese.

What does metabolically healthy mean? It is defined as having no increased risk of diabetes or cardiovascular disease (heart disease and stroke) because blood pressure, cholesterol levels and inflammatory biomarkers remain within normal limits.

However, read on before thinking that obesity can be equated with health. Though several studies may suggest metabolic health with obesity, there is a caveat: Some of these obese patients will go on to become metabolically unhealthy; but even more importantly, obesity will increase their risk significantly for a number of other chronic diseases. These include osteoarthritis, diverticulitis, rheumatoid arthritis and migraine. There is also a higher rate of premature mortality, or death, associated with obesity. In other words, the short answer is that obesity is NOT healthy.

Metabolically healthy obesity

Several published studies imply that there is such a thing as “metabolically healthy obesity,” or MHO. In the Cork and Kerry Diabetes and Heart Disease Phase 2 Study, results show that approximately one-third of obese patients may fall into the category of metabolically “healthy” (3). This means that they are not at increased risk of cardiovascular disease, based on five metabolic parameters, including LDL “bad” cholesterol, HDL “good” cholesterol, triglycerides, fasting plasma glucose and insulin resistance. The researchers compared three groups: MHO, metabolically unhealthy obese and nonobese participants. Both the MHO participants and the nonobese patients demonstrated these positive results.

There were over 2,000 participants involved in this study, with an equal proportion of men and women ranging in age from 45 to 75. The researchers believe that a beneficial inflammation profile, including a lower C-reactive protein and a lower white blood cell count, may be at the root of these results.

In the North West Adelaide Health Study, a prospective (forward-looking) study, the results show that one-third of obese patients may be metabolically healthy, but it goes further to say that this occurs in mostly younger patients, those less than 40 years old, and those with a lower waist circumference and more fat in the legs (4). The reason for the positive effects may have to do with how fat is transported through the body.

In metabolically unhealthy obese patients, fat is deposited in the organs, such as the liver and heart, potentially leading to cardiovascular disease and type 2 diabetes. A theory is that mitochondria, the cells’ energy source, are disrupted, potentially increasing inflammation.

However, the results also showed that over a 10-year period, one-third of “healthy” obese patients transitioned into the unhealthy category. Over a longer period of time, this number may increase.

Premature mortality

To hammer the nail into the coffin, so to speak, obesity may be associated with premature mortality. In one study, about 20 percent of American patient deaths were associated with being obese or overweight (5). The rates were highest among white men, white women and black women. The researchers found this statistic surprising; previous estimates were far lower. Researchers reviewed a registry of 19 consecutive National Health Interview Surveys, from 1986 to 2004, including more than 500,000 patients with ages ranging from 40 to 84.9 years old.

Interestingly, obesity seems to have more of an effect on mortality as we age: obesity raised mortality risk 100 percent in those who were 65 and over, compared to a 25 percent increased risk in those who were 45.

Osteoarthritis

It is unlikely that any group of obese patients would be able to avoid pressure on their joints. In an Australian study, those who were obese had a greater than two times increased risk of developing osteoarthritis of the hip and a greater than seven times increased risk of developing osteoarthritis of the knee (6). If this weren’t bad enough, obese patients complained of increased pain and stiffness, as well as decreased functioning, in the hip and knee joints. There were over 1,000 adults involved in this study. Patients who were 39 years or older demonstrated that obesity’s impact on osteoarthritis can affect those who are relatively young.

There is a solution to obesity and its impact on osteoarthritis of the knees and hips. In a randomized controlled trial of 454 patients over 18 months, those who lost just 10 percent of their body weight saw significant improvement in function and knee joint pain, compared to those who lost less than 10 percent of their body weight (7). So, if you are 200 pounds, this would mean you would experience benefits after losing only 20 pounds.

When diet and exercise together were utilized, patients saw the best outcomes, with reduced pain and inflammation and increased mobility, compared to diet or exercise alone. However, diet was superior to exercise in improving knee joint pressure. Also, inflammatory biomarkers were reduced significantly more in the combined diet and exercise group and in the diet alone group, compared to the exercise alone group.

The diet was composed of two shakes and a dinner that was vegetable rich and low in fat. The exercise component involved both walking with alacrity plus resistance training for a modest frequency of three times a week for one hour each time. Thus, if you were considering losing weight and did not want to start both exercise and diet regimens at once, focusing on a vegetable-rich diet may be most productive.

While it is interesting that some obese patients are metabolically healthy, this does not necessarily last, and there are a number of chronic diseases involved with increased weight. Though we should not be prejudiced or judgmental of obese patients, this disease needs to be treated to avoid increased risk of mortality and increased risk of developing other diseases.

References: (1) CDC.gov. (2) Health Aff. September/October 2009;vol. 28 no. 5 w822-w831. (3) J Clin Endocrinol Metab online. 2013 Aug. 26. (4) Diabetes Care. 2013;36:2388-2394. (5) Am J Public Health online. 2013 Aug. 15. (6) BMC Musculoskelet Disord. 2012;13:254. (7) JAMA. 2013;310:1263-1273.

Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com or consult your personal physician.