Weight-loss & macronutrient diets
Low-fat diet
Restricts dietary fat, traditionally to under 30% of energy, with greater emphasis on carbohydrates and lean protein.
What people typically eat
Fruit, vegetables, wholegrains, beans, lean meat, fish and low-fat dairy; cooking with little added fat.
What is restricted
Oils, butter, fatty meats, full-fat dairy, fried foods, pastries and many processed snacks.
Why people try it
The dominant weight-loss advice of the 1980s-2000s; still used for gallbladder and pancreatic conditions.
Realistic advantages
- Fat is energy-dense, so cutting it lowers calories automatically
- Low-fat, high-fibre versions align well with heart-healthy guidance
- Easy to understand and apply
Realistic disadvantages
- Low-fat processed products often replace fat with sugar and starch
- Very low fat impairs absorption of fat-soluble vitamins and can leave meals unsatisfying
- Head-to-head trials show no advantage over low-carb when calories match
Strength of evidence
Moderate evidence
Decades of trial data show modest weight loss; superiority over other calorie-controlled approaches is not demonstrated.
Likely cost and difficulty
Low-to-moderate cost; low difficulty.
Nutritional risks
Low; extreme versions risk essential-fatty-acid and fat-soluble-vitamin shortfalls.
Who should avoid it
No specific group; very-low-fat versions need care in children.
Is professional supervision advisable?
Not usually required.
References
Written by the Slimr editorial team. How we review diets.
