Weight-loss & macronutrient diets
Low-calorie diet
A structured programme providing roughly 800 to 1,200 calories daily, depending on the programme and the individual, usually for a defined period.
What people typically eat
Measured meals within the calorie cap, sometimes conventional food, sometimes formula products, with an emphasis on protein and vegetables.
What is restricted
Total energy is tightly capped; high-calorie foods are effectively excluded by the budget.
Why people try it
Faster weight loss than standard dieting, and, in programmes like DiRECT, type 2 diabetes remission.
Realistic advantages
- Produces faster, larger initial weight loss than moderate restriction
- Used successfully in NHS type 2 diabetes remission pilots
- Clear structure removes daily decision-making
Realistic disadvantages
- Hunger, fatigue, coldness and constipation are common early on
- Weight regain is frequent without a planned maintenance phase
- Not suitable for casual, unsupported use
Strength of evidence
Moderate evidence
Good trial evidence in supervised programmes, particularly for diabetes remission; long-term maintenance remains the weak point.
Key studies
Likely cost and difficulty
Low-to-moderate cost; high difficulty due to hunger and social restriction.
Nutritional risks
Gallstones, muscle loss and nutrient gaps if prolonged or unsupervised.
Who should avoid it
Pregnant or breastfeeding women, under-18s, people with eating disorders, and frail older adults.
Is professional supervision advisable?
Advisable, these programmes are designed to be delivered with clinical support.
References
Written by the Slimr editorial team. How we review diets.
