Must heavier patients lose more weight?
To answer this question, it is important to think in terms of percent weight loss rather than pounds or kilograms. In large studies of lifestyle intervention, of course individuals with higher BMI lost more weight. But the percentage weight loss was the same across BMI categories: class 1 (BMI 30-35), class 2 (BMI 35-40), class 3 (BMI > 40). Furthermore, the improvement in risk factors was the same across BMI categories. Those with class 3 obesity had the same improvements as those with class 1. This provides further rationale for thinking about weight loss as a percentage from baseline weight rather than as simply a weight-loss goal in pounds.
Goal setting is an important part of any behavioral intervention
At the start of a weight-loss intervention, the health care provider should raise the issue of the goal and the time course for achieving it. Patients often have unrealistic expectations, wanting to achieve large amounts of weight loss rapidly. Unfortunately, popular culture has reinforced this idea with advertisements using “lose 10 pounds the first week” and promoting before-and-after pictures of weight-loss results. The job of the health care provider is to coach and guide the patient in terms of achievable weight loss that can bring health improvement safely. Managing patient expectations is critical to long-term success.
Think in terms of percentage weight loss, not pounds, and set goals at achievable time points
Help patients translate a percent weight-loss goal to a pounds goal at 3, 6, and 12 months. With the emergence of medications approved for chronic weight management with robust weight-loss efficacy, it now is possible to achieve a weight-loss goal of 10% or 15% with regularity, and some patients will be able to achieve 20% or 25% weight loss with newer medications.
We should help our patients set a goal by calculating a goal for certain time points. A good goal for 3 months would be 5% weight loss. For our 200-lb patient, we would translate that to 10 lb in 3 months. For 6 months, the goal should be 10% (20 lb for our 200-lb patient). The usual trajectory of weight loss with lifestyle intervention alone is for a “plateau” at 6 months, although with newer medications, weight loss will continue for more than a year. That 1-year goal might be 15% (30 lb for our 200-lb patient) or even more, based on the patient’s baseline weight and body composition.
Weight-loss calculators can be useful tools for patients and health care providers. They can be found online and include the National Institutes of Health Body Weight Planner and the Pennington Biomedical Weight Loss Predictor Calculator. These tools give patients a realistic expectation of how fast weight loss can occur and provide guidelines to measure success.
Can patients lose too much weight?
In this patient population, losing too much weight is not typically a concern. However, newer medications are achieving average weight losses of 17% and 22% at 62 weeks, as reported by this news organization. There is a wide variation in response to these newer agents which target appetite, and many patients are losing more than the average percentages.
Remembering that the goal of weight loss is the reduction of excess abnormal body fat, we want patients to preserve as much lean mass as possible. Weight-bearing exercise can help during the weight-loss phase, but large or rapid weight loss can be concerning, especially in older individuals. When the BMI drops below 25, we want to watch patients carefully. Measurement of body composition, including bone mineral density, with dual-energy x-ray absorptiometry (DEXA) can help. This is a scenario where dose reduction of antiobesity medication can be indicated, and good clinical judgment is required to keep weight loss at healthy levels.
The future of weight loss
In the past, our strategy has been to promote as much weight loss as possible. With more effective medications, our strategy will have to change to a treat-to-target approach, such as we already use in hypertension and diabetes.
With the ability to produce powerful effects on appetite will come the need to not only target weight loss but to target preservation of lean mass and even to target different approaches for weight-loss maintenance. At present, we have no evidence that stopping medications results in anything other than weight regain. The study of different approaches to weight-loss maintenance will require our full attention.
Dr. Ryan has disclosed the following relevant financial relationships: Serve(d) as a director, officer, partner, employee, consultant, or trustee for: Altimmune; Amgen; Calibrate; Epitomee; Gila; Lilly; Novo Nordisk; Scientific Intake; Wondr Health; Xeno Biosciences; YSOPIA; Zealand. Received income in an amount equal to or greater than $250 from: Altimmune; Amgen; Calibrate; Epitomee; Gila; Lilly; Novo Nordisk; Scientific Intake; Wondr Health; Xeno Biosciences; YSOPIA; Zealand.
Donna Ryan, MD, is Professor Emerita, Pennington Biomedical Research Center, Louisiana State University, New Orleans.
A version of this article first appeared on Medscape.com.