In order to lose weight the body has to be in a state of negative energy balance. Treatments for obesity therefore need to focus on helping individuals to reduce their intake of energy dense foods and to increase their levels of physical activity.

An energy deficit of 500 kcal/day has been shown to be sufficient for most people to achieve an average weekly weight loss of 0.5 kg.²⁴

• A 500 kcal/day energy deficit can often be achieved by basing advice on the ‘Balance of Good Health’
• The most energy dense foods tend to be high in fat and/or sugar and focusing attention on these aspects of diet will help to reduce overall energy intake
• Alcohol is another consideration, with both its appetite-stimulating effects and considerable energy content
• It is essential to look at the portion sizes of the foods consumed and many people need guidance on suitable portion sizes

It has been noted that there has been a gradual increase in the portion sizes of many common foods. For example, fast food portions of french fries, hamburgers and soda are 2–5 times larger than originally. Crisps have increased in size from 28 g packets to 40–60 g packets.²⁵

Today’s consumers have become conditioned to larger serving sizes in meals and snacks and the need for greater attention to food portion size should be emphasized in weight management.^26,27 One useful exercise may be for patients to record and weigh the amounts of foods that they eat – a simple pocketbook calorie counter could give some patients the skills to estimate the energy content of common foods.