How to Read Food Labels: A Practical Guide for Weight Management

The traffic light system

Most food products sold in the UK display a front-of-pack traffic light label showing the amount of energy (calories), fat, saturated fat, sugars, and salt per serving or per 100 g, colour-coded red, amber, or green. Red indicates a high amount, amber a medium amount, and green a low amount. For weight management, the most useful figures to focus on are total energy (calories) and total fat — though the traffic light system provides a quick visual guide to the overall nutritional profile of a product.

Understanding the nutrition information panel

The detailed nutrition information panel on the back or side of a product shows values per 100 g (or 100 ml for drinks) and typically also per serving. The per-100 g column is the most useful for comparing products — it allows direct comparison regardless of serving size. The per-serving column tells you what you will actually consume if you eat the stated serving size, but serving sizes are often unrealistically small.

Key figures to check:

• Energy (kcal) — the total calorie content. For weight management, this is the most important figure. A rough guide: foods providing more than 400 kcal per 100 g are energy-dense; those providing less than 100 kcal per 100 g are low energy density.
• Total fat — fat provides 9 kcal per gram, more than double the 4 kcal per gram provided by carbohydrate or protein. High-fat foods are typically energy-dense.
• Saturated fat — associated with raised LDL cholesterol and cardiovascular risk. The UK recommendation is to keep saturated fat below 20 g/day for women and 30 g/day for men.
• Total sugars — includes both naturally occurring sugars (in fruit, dairy) and added sugars. For weight management, added sugars are the primary concern — they provide calories with minimal satiety.
• Fibre — higher-fibre foods tend to be more satiating and support gut health. A food is considered high in fibre if it contains 6 g or more per 100 g.
• Protein — protein is the most satiating macronutrient. Higher-protein foods support appetite control and muscle preservation during weight loss.

Common label claims and what they actually mean

• Low fat — legally defined as 3 g or less of fat per 100 g. However, low-fat products often contain more sugar than their full-fat equivalents to compensate for flavour.
• Reduced fat — contains at least 30% less fat than the standard version. This does not mean the product is low in fat or calories.
• No added sugar — no sugar has been added, but the product may still contain significant naturally occurring sugars (e.g. fruit juice).
• Light or lite — must contain at least 30% less of a nutrient (usually fat or calories) than the standard version, but the baseline product may still be energy-dense.
• High protein — legally defined as protein providing 20% or more of the product's total energy. Genuinely useful for satiety and muscle preservation.

Practical tips for using labels in weight management

Rather than scrutinising every label, focus on a few key habits: check the per-100 g calorie figure when comparing similar products; be sceptical of health claims on the front of pack; prioritise foods with short ingredient lists and recognisable ingredients; and remember that the most nutritious foods — vegetables, fruit, lean protein, legumes — often have no label at all.

Book a consultation with Weight Loss Wales for personalised nutritional guidance as part of your weight management programme.