Symptom
Why can't I lose weight?
If eating less and exercising more has stopped working, there are usually several contributors worth assessing. Weight that will not shift is a clinical question rather than a willpower question.
In short
Weight that will not shift usually reflects a combination of factors: total energy intake, adaptive changes after repeated dieting, reduced activity, poor sleep, sustained stress, medicines that promote weight gain, loss of muscle mass, and individual biology. Metabolic and hormonal conditions such as insulin resistance, an underactive thyroid, perimenopause or low testosterone can contribute in some people, but they are not the explanation in everyone. Assessment establishes which of these apply to you before treatment is chosen.
Medically reviewed by Dr Arnav Kapur, MBBCh Cum Laude
The approach
Understand first. Then treat.
Repeated restrictive dieting can reduce muscle mass and lower total energy expenditure, which makes each subsequent attempt feel harder. Hormonal and metabolic changes can also alter appetite and where the body stores fat.
We investigate the reasons first, then build treatment around what we find, which may or may not include medication.
What we investigate
- Insulin resistance, fasting insulin, HbA1c and glucose handling
- Thyroid function, including full thyroid panel and antibodies where indicated
- Perimenopause, menopause and female hormone patterns
- Testosterone and male hormonal health
- Body composition, including fat mass, lean mass and visceral fat
- Sleep quality, sleep apnoea risk, stress and cortisol rhythm
- Nutrition, protein intake and eating patterns
- Medicines that promote weight gain, and gut health
Insulin resistance can be one contributor
When insulin is persistently high, appetite and fat storage patterns can change. Fasting glucose may look normal while insulin is raised. Insulin and HOMA-IR are not diagnostic tests on their own, so they are interpreted alongside HbA1c, glucose, waist measurement and the wider clinical picture.
Hormonal change through midlife
Perimenopause and menopause shift fat distribution towards the abdomen and reduce insulin sensitivity, even without changes in diet. In men, low testosterone can reduce muscle mass and drive. Both can be assessed and, where appropriate, treated.
Muscle is metabolic
Bioimpedance analysis separates fat from muscle, which shows whether previous dieting cost lean tissue. Rebuilding muscle with protein and resistance training supports strength, function and glucose handling. The effect on resting metabolic rate is modest, so it supports rather than replaces attention to overall energy intake.
Where medication fits
GLP-1 based medicines can be effective for selected patients, prescribed only after assessment and used alongside nutrition, training and sleep work. They are a tool within a plan, not the plan itself.
Common questions
Answers before you book.
Could my thyroid be the reason?
An underactive thyroid can cause modest weight gain, fatigue, cold intolerance and hair changes, and thyroid function is easily measured. Symptoms alone do not indicate thyroid disease, and thyroid problems explain only a small proportion of weight difficulty.
Why is weight harder after 40?
Hormonal change, gradual muscle loss, reduced activity, poorer sleep and a higher stress load can all play a part. Several of these can be addressed once identified.
Do I need weight loss injections?
Not necessarily. Some people respond well once hormonal, metabolic, sleep and nutritional contributors are corrected. Medication is discussed if it is clinically appropriate for you.
This page is general health information and is not medical advice. Investigation and treatment follow individual clinical assessment.
Ready to start properly?
- Medical weight loss consultation
- Weight loss injections in Johannesburg
- Metabolic health and diabetes
- Book a consultation
Centre of Advanced Medicine, 13 Scott St, Waverley, Johannesburg
Monday to Friday, 07:40 to 17:00
011 440 8721