Open Access
Feature Article

How to investigate weight gain in an adult. ‘I’ve put on so much weight, doc’

Open Access
Feature Article

How to investigate weight gain in an adult. ‘I’ve put on so much weight, doc’

Ramy H Bishay, Nic Kormas

Figures

© avid creative/istockphoto. MODEL USED FOR ILLUSTRATIVE PURPOSES ONLY.
© avid creative/istockphoto. MODEL USED FOR ILLUSTRATIVE PURPOSES ONLY.
Dr Bishay is an Advanced Trainee in Endocrinology at Concord Repatriation General Hospital and an honorary associate of the Sydney Medical School, University of Sydney. Dr Kormas is Head of the Metabolic Rehabilitation Programs at Concord Repatriation General and Camden Hospitals in Sydney, NSW; Senior Staff Specialist Endocrinologist at these hospitals; and Co-ordinator of the publicly funded bariatric program of the Sydney Local Health District. SERIES EDITOR: Dr Bernard Champion, BEc, MB BS, BSc(Med)(Hon 1), FRACP, MMedEd, is a Lecturer at Sydney Medical School Nepean and The University of Sydney; and Head of Department – Endocrinology and Diabetes, Nepean Blue Mountains Local Health District, Penrith, NSW.

 

What are the key features to assess in the clinical examination?

It is important to weigh patients and measure their height to obtain an accurate BMI, as well as measure their waist circumference. Features of endocrinopathies should be sought (see below). The presence of goitre may alert to contributing thyroid disease but is also important in the setting of OSA. 

Examination of the patient’s lower limbs and feet is important as many severely obese patients cannot see or reach their feet. Peripheral oedema, neuropathy tested with monofilament testing if diabetes is present, and vascular disease (e.g. absent peripheral pulses, hair loss or eczema of chronic venous insufficiency) should be documented. Examination for infections in skin folds should also be performed.

 

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What else could be causing this patient’s weight gain?

Endocrinopathies are relatively rare causes of weight gain and, when present, usually amount to about 20 kg in weight gain (Table 3). For example, only a small proportion (<3%) of obese patients with type 2 diabetes will have Cushing’s syndrome so routine screening is not recommended unless more specific features are present (e.g. proximal weakness, easy bruising, wide-purplish abdominal striae, etc.).11 Hypothyroidism rarely leads to massive weight gain and can be easily diagnosed on thyroid function tests.12 Insulinomas can lead to progressive weight gain but are very rare and usually result in recurrent symptomatic hypoglycaemia. 

If an endocrinopathy is suspected, specialist referral is indicated.

 

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What initial investigations are necessary?

Investigations should be aimed at categorising Virginia’s cardiometabolic risk (e.g. use of the Australian absolute cardiovascular disease risk calculator, www.cvdcheck.org.au) and fitness for exercise, establishing baseline clinical parameters prior to treatment, and assessing for contributing factors to weight gain (Table 4). Undiagnosed OSA and/or obesity hypoventilation syndrome is common in obese patients. Symptoms of OSA (daytime somnolence, drifting asleep while driving or watching TV, waking up unrefreshed) should prompt a referral for a sleep study. Nutritional deficiency is common and vitamin B12 (especially if taking metformin) and vitamin D levels should be assessed and supplemented accordingly. 

 

What is the best course of action for  this patient?

The error most overweight or obese patients and clinicians make is that they believe a lack of exercise is the main problem for the ongoing gain of weight. Experience teaches, however, that ‘You can easily out-eat what you run’. For example, one hour of moderate intensity activity in an obese person equates to approximately 350 kcal (1465 kJ). However, eating energy-dense food equates to an ingestion of an average of 70 kcal every minute (about 300 kJ/minute), and therefore it takes only five minutes of eating this type of food to negate an hour of exercise. 

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The first step therefore with an overweight or obese patient wanting to lose weight, such as Virginia, is appropriate education regarding their current energy (caloric) intake as well as that required for gradual weight loss. The advice of an experienced dietitian is essential. In general, a negative energy balance of 500 kcal or 1000 kcal each day (about 2100 or 4200 kJ/day, respectively) equates to 0.5 or 1 kg of weight loss per week, respectively. In reality, obese patients will lose much more than this initially because fat, muscle and fluid are lost; weight training exercise should therefore be commenced to preserve muscle bulk and limit bone density loss.