Hale Handbook

Low-Fat Diets: What's Left After the 1990s

Low-fat eating fell out of fashion, partly for good reasons. Done with whole foods, it's still a valid way to lose weight.

2 min readUpdated November 2026Not reviewed by a doctor

The short version

  • A low-fat diet usually means less than about 30% of calories from fat. Very-low-fat means under about 15%.
  • It works about as well as low-carb on average, and in head-to-head trials low-carb sometimes has a slight edge.
  • The old mistake was replacing fat with sugar and refined starch. Choose beans, vegetables and whole grains.
  • Don't cut healthy fats like olive oil, nuts and fish too far.
In a sentence
Limit fat, and fill up on whole grains, beans, vegetables and fruit.
How restrictive
Counting needed?
Fat grams, usually
Quality of evidence
Moderate
Typical cost
Low
Main drawback
Easy to fill the gap with sugar and refined carbs

See how this compares with every other diet →

What it is

Fat has about 9 calories a gram compared with 4 for protein and carbs, so cutting it is an easy way to cut calories. Most plans limit it to about 20 to 30% of daily calories. Very-low-fat programs like Ornish go to 10 to 15% and are mostly plant-based.

What went wrong in the 1990s

As low-fat became the official message, food companies filled shelves with fat-free cookies and snacks loaded with sugar and refined starch. Many people ate more of them and gained weight. "Low-fat" and "healthy" weren't the same thing then, and they aren't now.

What the evidence says

Weight. A review of 53 trials found low-fat diets did about as well as other weight-loss diets when intensity was similar, and slightly less well than low-carb, with a difference of about 2.5 pounds. In the well-run DIETFITS trial, healthy low-fat and healthy low-carb came out almost even.

Heart health. Low-fat diets usually lower LDL cholesterol, particularly when they cut saturated fat. But cutting healthy fats alongside it isn't a win. Studies favor replacing saturated fat with unsaturated fat or whole grains, not refined carbs.

How to do it well

  • Fill your plate with vegetables, fruit, whole grains, beans and lean protein.
  • Use smaller amounts of oil, nuts and avocado instead of cutting them out.
  • Choose lean meats and fish, and keep eating fatty fish like salmon.
  • Don't treat "low-fat" on a label as a green light. Check the added sugar. See food labels.
  • Watch your portions of pasta, rice and bread, as these can quietly replace the calories you've saved.

A sample day

  • Breakfast: Oatmeal with fruit and nonfat milk
  • Lunch: Black bean soup, a whole-grain roll and a salad with light dressing
  • Snack: Apple and plain nonfat yogurt
  • Dinner: Grilled white fish, brown rice and plenty of roasted vegetables

Pros and cons

Good: Inexpensive, high in volume, and nutritious when built on whole foods.

Harder: Less filling for some people, and meals can feel bland. Very-low-fat diets are hard to keep up, and can raise triglycerides in some people if they're high in refined carbs.

Sources

  1. Gardner et al., JAMA (2018): Low-fat vs low-carb diet (DIETFITS)
  2. Tobias et al., Lancet Diabetes & Endocrinology (2015): Low-fat diets vs other diets on long-term weight
  3. Harvard T.H. Chan School of Public Health: Fats and Cholesterol

This guide is general information, not medical advice. Please check with a clinician before making big changes, especially if you have a health condition, take medication, or are pregnant. Read the full disclaimer.

Keep reading