If you have lost weight before and watched it return, you are in very large company. Regain is one of the most common experiences in weight management, and the reasons are mostly biological.
The body defends its weight
When body weight falls, the body responds as if food were scarce. In a well-known study, adults who lost weight on a very-low-energy diet had lower levels of the fullness hormone leptin and higher levels of the hunger hormone ghrelin. They also reported more hunger. These changes were still present a year later.[1]
Regain is the body doing what it evolved to do. Planning for it is simply good medicine.
Medication works only while it’s taken
Anti-obesity medicines counter some of this biology. When they are stopped, the biology comes back. In the STEP 1 extension, people who stopped semaglutide regained about two-thirds of their lost weight within a year.[2] This is similar to blood pressure rising after stopping a blood pressure medicine.
What a maintenance plan includes
- Regular follow-up. Behavioral programs that help people keep weight off typically include many sessions over one to two years, not a single visit.[3]
- Physical activity. Activity matters more for keeping weight off than for losing it. The Diabetes Prevention Program paired a modest weight-loss goal with about 150 minutes a week of activity, such as brisk walking.[4]
- Self-monitoring. Regular weighing, food awareness and noticing early drift make small corrections easier than large ones.
- Protein, sleep and stress. Each affects appetite and energy, and each is easy to overlook.
- A decision about medication. Some people continue medication long term. Others transition carefully. That decision is made together, not by running out of a prescription.
If weight has already returned
Regain is information, not a verdict. It usually points to something that changed: a medication, a life event, sleep, stress, an injury. A fresh evaluation looks for the cause and adjusts the plan. Even keeping some of the weight off counts. In the Diabetes Prevention Program, a modest weight loss reduced the incidence of type 2 diabetes by 58% compared with placebo.[4]
Sources and references
- Sumithran P, Prendergast LA, Delbridge E, Purcell K, Shulkes A, Kriketos A, Proietto J. Long-term persistence of hormonal adaptations to weight loss. N Engl J Med. 2011;365(17):1597-1604. View source
- Wilding JPH, Batterham RL, Davies M, Van Gaal LF, Kandler K, Konakli K, et al.; STEP 1 Study Group. Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension. Diabetes Obes Metab. 2022;24(8):1553-1564. View source
- US Preventive Services Task Force; Curry SJ, Krist AH, Owens DK, et al. Behavioral weight loss interventions to prevent obesity-related morbidity and mortality in adults: US Preventive Services Task Force recommendation statement. JAMA. 2018;320(11):1163-1171. View source
- Knowler WC, Barrett-Connor E, Fowler SE, Hamman RF, Lachin JM, Walker EA, Nathan DM; Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002;346(6):393-403. View source
This answer is general education for adults and isn’t a substitute for a personal medical evaluation. Individual results vary. In an emergency, call 911.