In the 1960s, medical organizations like the American Heart Association began recommending people reduce their risk of heart disease by cutting intake of dietary fat, particularly the saturated fat found in meat and dairy products.
In the 1970s, the U.S. government issued the Dietary Goals for the United States, urging Americans to eat no more than 30 percent of their calories from fat, and no more than 10 percent of their calories from saturated fat.
In the 1980s, the government published the first edition of Dietary Guidelines for Americans, which established low-fat eating as public policy.
Dietary recommendations are rarely unanimous, however. As low-fat became a standard recommendation, some medical experts touted high-fat, high-protein, low-carbohydrate diets as the best path to good health.
Fast forward to 2025. Fattier diets like keto, paleo, and Mediterranean tend to dominate the conversation about better health. But that doesn’t mean the benefits of low-fat eating have been disproven.
A low-fat diet is the most scientifically supported, the simplest to implement, and the most effective way to prevent or treat chronic conditions like high blood pressure, heart disease, diabetes, obesity, Alzheimer’s disease, and several types of cancer, including leading killers like colon and breast.
Strong evidence
Several major studies show that a low-fat diet is healthy. Researchers from the Physicians Committee and Yale School of Medicine studied 244 people with an average age of 54. Of those, 122 went on a low-fat, vegan diet for 16 weeks, and 122 were in a control group that didn’t make dietary changes. A vegan diet is a plant-based dietary pattern that doesn’t include any animal products. Emphasizing fruits and vegetables, whole grains, legumes and beans, and nuts and seeds, it’s naturally low in saturated fat and cholesterol, high in fiber, and rich in nutrients.
The difference between the two groups was dramatic.
Weight loss. After 16 weeks, the people on the low-fat diet had lost an average of 13 pounds. The control group had no weight loss.
Faster metabolism. The low-fat group developed a more efficient metabolism, with post-meal calorie-burning rising 14 percent compared with the control group.
Improved blood sugar control. Insulin resistance—when cells don’t respond well to the hormone that moves blood sugar out of the bloodstream and blood sugar levels rise—is a risk factor for prediabetes and type 2 diabetes.
The low-fat group had a significant drop in insulin resistance. (A drop in insulin resistance means there is a corresponding increase in insulin sensitivity, or the ability of cells to respond to insulin.) The control group had no change in insulin resistance.
Liver health. The low-fat group had a 34 percent reduction in fat in the liver, reducing the risk of cardiovascular disease, type 2 diabetes, fatty liver disease, cirrhosis, liver cancer, and liver failure. The control group had no decrease.
“A low-fat, plant-based dietary intervention reduces body weight by reducing energy [calorie] intake and increasing postprandial [post-meal] metabolism,” wrote the researchers in the Nov. 30, 2020, issue of JAMA Network Open.
“These changes are associated with increased insulin sensitivity.”
Longer life. A 20-year study of nearly 49,000 women from researchers at Fred Hutchinson Cancer Research Center in Seattle found that a low-fat diet produced significant benefits across several conditions:
- 15 to 35 percent reduction in deaths from all causes after you’ve had breast cancer
- 13 to 25 percent reduction in insulin-
dependent diabetes, a form of the disease that requires insulin shots to stabilize blood sugar
- 15 to 30 percent reduction in heart disease among 23,000 women who didn’t have high blood pressure or heart disease at the beginning of the study.
How to cut fat
The typical American diet contains 36 percent fat. But don’t try to lower your percentage of fat—fat percentages are nearly impossible to track. Instead, simply reduce or avoid high-fat foods—mainly, animal and full-fat dairy products, both of which are high in saturated fat. You can transition to a low-fat, plant-based diet in two easy steps.
1. Choose foods you really like
First, identify healthy breakfasts, lunches, and dinners that you really like. Most of us stick to a few, favorite meals. We may have eight or nine different dinners we like, and we pick from that repertoire night after night. All you need to do is find the meals that suit your tastes—and you’re set.
Breakfast ideas
- Old-fashioned oats (not instant or one-minute varieties, which drive up blood sugar) topped with cinnamon, raisins, berries, or a mix of fruits
- Veggie sausage or veggie bacon, which are tasty and high in protein
- Scrambled tofu, which is a great substitute for scrambled eggs when topped with salsa or combined with tasty spices such as onion powder, salt, turmeric or cumin
- Breakfast burritos, which you can buy frozen and pop in a microwave.
Lunch ideas
For lunch, focus on salads, soups, and sandwich wraps:
- Try a three-bean salad.
- Choose dried soup mixers as a time saver.
- Or enjoy a BLT with veggie bacon, lettuce, and tomato.
Dinner ideas
Dinner presents a limitless array of healthful foods:
- Whole-grain pasta
- Beans and rice
- Soft tacos
- Veggie lasagna
- Rice and vegetables
- Fat-free vegetarian burgers
- Mushroom stroganoff, just to name a few.
For a well-balanced dinner, fill about a quarter of your plate with a legume dish (baked beans, bean burrito, or black-eyed peas), another quarter with a starchy food (brown rice, a yam, or pasta) and the remaining half with vegetables. Add fruit for dessert.
2. Commit for Three Weeks
After you pick your favorite meals, mark a three-week period on your calendar and commit yourself completely to the diet for those 21 days. Why three weeks? Fat and sugar cravings—programmed into the body as a survival mechanism to guarantee the consumption of high-calorie foods during times of famine—last about three weeks. After that period, you’ll be surprised how little you miss the fatty foods you’ve left behind. Instead, you’ll begin to appreciate the natural sweetness of an apple, and the fat in a typical restaurant’s stir fry will taste greasy and unpleasant.
