It is important not to cut carbohydrates significantly on days that you are exercising strenuously, as this will negatively affect your energy level and will probably result in loss of lean body mass (muscle, bone, and water) which can impair weightloss efforts long term.
The approved labeling for Belviq recommends that the drug be discontinued in patients who fail to lose 5 percent of their bodyweight after 12 weeks of treatment, as these patients are unlikely to achieve clinically meaningful weightloss with continued treatment.
People taking the lower dose of Qsymia who do not lose 3% of their bodyweight after 12 weeks are unlikely to achieve a sustained weightloss on the same dose.
And if the scale really refuses to budge, focus on maintaining your weightloss, as losing nearly 20% of your bodyweight is fantastic and will significantly improve your health in the long run.
This is because they rely on static models of weightloss rather than dynamic models that account for the way the body adjusts to reducing food intake by reducing energy expenditure.