Diet and Physical Activity Reduces Cardiometabolic Risk in Severe Obesity

One of the important indications for weight loss in people with excess weight is to reduce their risk for cardiometabolic complications.

But, as regular readers of these pages are aware by now, diet and exercise may be of limited benefit, especially in individuals with severe obesity.

So exactly how effective are such lifestyle interventions in this population?

This question was now addressed in a randomised controlled trial by Bret Goodpaster from the University of Pittsburgh, PA, and colleagues in a paper recently published in JAMA.

In order to determine the efficacy of a weight loss and physical activity intervention on the adverse health risks of severe obesity, 130 (37% African American) severely obese (class II or III) adult participants without diabetes were enrolled in a one-year intensive lifestyle intervention consisting of diet and physical activity.

However, while one group was randomised to diet and physical activity for the entire 12 months, the other group had the identical dietary intervention but with physical activity starting after 6 months.

A total of 101 (78%) subjects completed the 12-month follow-up assessments.

At 6 months, the initial-activity group lost around 11 Kg whereas the delayed-activity group lost around 8 kg. At 12 months, the corresponding weight loss was around 12 and 10 Kg, respectively.

Not unexpectedly, associated with this weight loss was a significant reduction in waist circumference, visceral abdominal fat, hepatic fat content, blood pressure, and insulin resistance were all reduced in both groups.

While the study shows that diet and exercise alone (irrespective of whether or not exercise is added from the start or after 6 months of dietary weight loss) can lead to significant weight loss with improvement in cardiometabolic risk factors, the question of course remains whether or not these changes remain sustainable.

As we know, most patients tend to regain weight over time and it is highly likely that weight regain will result in a worsening in cardiometabolic risk factors.

Nevertheless, the study shows that even in individuals with severe obesity, clinically meaningful weight loss is possible with diet and exercise alone, that it probably does not matter too much whether or not exercise is started on day one of the program, and that this may well be a reasonable strategy for individuals who can manage to stick with these lifestyle changes over time.

Obviously, whether such efforts are durable in the long term in a relevant number of individuals remains to be seen.

Edmonton, Alberta

Goodpaster BH, Delany JP, Otto AD, Kuller L, Vockley J, South-Paul JE, Thomas SB, Brown J, McTigue K, Hames KC, Lang W, & Jakicic JM (2010). Effects of diet and physical activity interventions on weight loss and cardiometabolic risk factors in severely obese adults: a randomized trial. JAMA : the journal of the American Medical Association, 304 (16), 1795-802 PMID: 20935337