Energy restriction and adherence required for weight loss without surgery Non-surgical weight loss treatment has not been shown to reduce mortality or cardiovascular morbidity, but can prevent diabetes mellitus and improves cardiovascular risk factors. For weight loss, energy restriction is fundamental and can lead to an average 2 to 20 kg loss over 6 to 12 months. Pharmacological treatment, behaviour therapy, physical activity and weight loss advice through web sites and smartphone applications and combinations in addition to energy restriction can contribute to further, but relatively limited weight loss up to 30 months. Adherence to the treatment is necessary for both weight loss and long-term weight loss maintenance.