Q&A | Why it’s important to eat — and eat well — when on weight-loss drugs

It’s no longer a Hollywood secret or shock to many a weight loss fanatic that weight-loss drugs such as Ozempic and Mounjaro have become a major facet in shedding impossible layers of body fat.

In a new study exploring weight gain after the use of weight-loss drugs, it was found that when people stop GLP‑1 medications, there is a risk of cardiometabolic risk coming back quickly, sometimes within a year.

The risk of prescribing GLP‑1s without structured exercise and nutritional support is setting patients up for failure. We speak to Dr Mosima Mabunda, the chief clinical officer at Vitality, to better understand who qualifies for weight-loss drugs and what causes weight gain after one stops using them.

When does someone qualify to take weight-loss medication?

Importantly, obesity is recognised as a chronic disease in South Africa’s new clinical guidelines for adult obesity. These guidelines emphasise that medication is not a shortcut; it is part of a structured long‑term treatment plan that includes nutrition therapy, physical activity, psychological support and ongoing review.

In South Africa, the decision to prescribe evidence‑based weight-loss medication (such as GLP-1 receptor agonists) is guided by clinical criteria, not appearance or personal preference.

We rely on established indications:

• For obesity: Patients generally qualify if they have a BMI in the obesity range (30kg/m²+), or a BMI of 27kg/m²+ with comorbidities such as type 2 diabetes, hypertension or abnormal cholesterol levels. These criteria align with South African Health Products Regulatory Authority (Sahpra) guidelines.
• A note on diabetes: GLP‑1 medications are also indicated for type 2 diabetes when glucose control is suboptimal despite lifestyle changes and first‑line therapies, especially when cardiovascular risk is present.

What causes the rapid weight gain after stopping GLP‑1 medications?

GLP‑1 medications work by reducing appetite, slowing gastric emptying and improving insulin regulation. When the medication is stopped, these physiological effects revert: appetite returns, metabolic rate shifts and the underlying biological drivers of weight gain resurface.

Recent evidence shows that after discontinuation, patients tend to regain most or all of the weight lost within about 1.7 years. This rebound is not a failure of the patient; it illustrates that obesity is a chronic, relapsing disease and many patients require long-term or lifelong treatment to maintain results, just as we would with hypertension or diabetes.

Can weight-loss medication be used with cosmetic procedures?

Yes, but with important cautions. Weight-loss medications such as GLP‑1s and cosmetic or body-sculpting procedures serve different purposes:

• Weight-loss medication addresses internal drivers of obesity and improves metabolic health.
• Cosmetic procedures reshape specific areas but do not treat the medical condition of obesity.

They can be combined safely when managed by qualified clinicians, particularly when the patient is medically stable, weight loss has plateaued, and there is a clear clinical or psychological benefit.

However, we advise patients that cosmetic procedures cannot replace metabolic treatment, and without ongoing nutrition, behavioural support and, when appropriate, pharmacotherapy, results from either intervention may not be sustainable.

As GLP‑1s suppress appetite, what foods should people prioritise to maintain nutrition, keep weight off and stay healthy?

A suppressed appetite means every bite matters. People using weight-loss medication must prioritise nutrient‑dense foods to prevent deficiencies, support muscle mass and sustain long‑term health.

We recommend focusing on:

• High‑quality protein: Supports muscle preservation during weight loss. Examples include legumes, lentils, tofu, fish, chicken, lean meats, eggs, dairy or fortified plant alternatives.
• High‑fibre foods: Enhance gut health, fullness and glucose control. Examples include oats, whole grains, beans, vegetables, fruits, nuts and seeds.
• Hydration: Many patients on GLP‑1s drink less water or skip meals unintentionally.
• Small, regular meals: Gentle, regular meals help stabilise energy and prevent nausea.
• Supplementation when clinically needed: Because reduced appetite may reduce micronutrient intake, clinicians may recommend supplementation depending on the patient’s diet and bloodwork.