Table of ContentsView AllTable of ContentsBackgroundHow It WorksPros and ConsHow It Compares
Table of ContentsView All
View All
Table of Contents
Background
How It Works
Pros and Cons
How It Compares
Low-fat diets, in which calories from fat sources are cut dramatically, were once considered the best way to reduce body fat and lower the risk of heart disease and even cancer. Today, more is known about how dietary fat affects the body. Recommendations now center on promoting some fats while limiting others.
What Experts Say"Low-fat diets were popular in the past for heart health, but we’ve learned more about them over time. Not all fats are created equal. There are healthy fats, like what we find in avocados and olive oil, and unhealthy fats—saturated and trans fats—which we should limit."—Kelly Plowe, MS, RD
What Experts Say
“Low-fat diets were popular in the past for heart health, but we’ve learned more about them over time. Not all fats are created equal. There are healthy fats, like what we find in avocados and olive oil, and unhealthy fats—saturated and trans fats—which we should limit."—Kelly Plowe, MS, RD
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The U.S. government has been providing dietary guidance for Americans for many years. The first edition of The Dietary Goals for the United States was published in 1977.
Dietary guidance has generally included advice about what to eat and drink for better health, but the specific messaging has changed throughout the years to reflect advances in nutritional understanding and the role of specific foods and nutrients on overall health.
The earliest guidance focused specifically on reducing how many people had diet-related diseases, such as cardiovascular disease and diabetes. Fat was identified as the primary culprit.
The guidelines, while well-intentioned, greatly influenced average Americans’ perception of a healthy diet. There was no distinction between “good” and “bad” fats. As a result, many people were avoiding otherwise-healthy foods based on their fat content alone.
Updated guidelines focus on finding a healthy balance of “good” fats and other important nutrients.
How Many Grams of Fat Your Body Needs Daily
In general, a low-fat diet is one in which no more than 30% of daily calories come from any fat source. On an individual food basis, the most-widely accepted definition of a low-fat food is one that has 3 grams of fat or less per 100 calories.
What to Eat
Compliant FoodsCarbohydratesProteinHeart-healthy fats (in moderation)Non-Compliant FoodsSaturated fats (in excess)Trans fats
Compliant FoodsCarbohydratesProteinHeart-healthy fats (in moderation)
Carbohydrates
Protein
Heart-healthy fats (in moderation)
Non-Compliant FoodsSaturated fats (in excess)Trans fats
Saturated fats (in excess)
Trans fats
Carbs are a necessary source of energy and you’ll find them in healthy, nutritious foods: fruits, vegetables, and whole grains. But if you’re looking to lose weight, be careful not to replace fats with low-fat foods that are actually high in sugar and refined flour (which arealsocarbohydrates).
Like fats, proteins help you feel full, so be sure to consume plenty of protein-rich foods. But to keep your diet lower in fat, chooselean protein sourcessuch as legumes, fish, skinless poultry, and lean cuts of beef.
Heart-Healthy Fats
There are two kinds of unsaturated fats, both of which are thought to help lower LDL (or “bad”) cholesterol levels:
Saturated Fats and Trans Fats
Saturated fats are found in animal products, such as meat, butter, and cream, and a few plant sources, including coconut and palm oil.
Trans fats are unsaturated fats that have been processed to make them more shelf-stable. They usually show up on food labels as “hydrogenated” or “partially hydrogenated” oils. While baked goods and other commercially prepared products in the U.S. are not allowed to contain trans fats (as of June 2018), they can still be found in fried foods.
ProsShort-term weight lossConsLittle evidence of health benefitsRestrictiveMental health risks
ProsShort-term weight loss
Short-term weight loss
ConsLittle evidence of health benefitsRestrictiveMental health risks
Little evidence of health benefits
Restrictive
Mental health risks
Pros
Short-Term Weight Loss
If you make an effort to reduce your fat intake, it is likely that you will lose weight. This holds true for most diets that restrict a certain type of food or macronutrient (such as carbohydrates). However, to keep this weight off, you will need to continue limiting fat in your diet.
A low-fat diet is likely to be healthy and may help you lose weight if it is still balanced with “good” fats and nutrient-rich carbohydrate and protein sources. But there are drawbacks to be aware of, most notably the change in expert advice regarding fat consumption.
Cons
Unclear Scientific Evidence
Many studies have been conducted to determine the extent of health benefits for people following low-fat diets. Overarchingly, the evidence does not support low-fat diets over other dietary interventions for long-term weight loss.
Additionally, evidence has suggested that following unhealthy low-fat diets may actually be associated with increased risk of death.
Some important vitamins (including vitamins A, D, E, and K) are fat-soluble, which means your body can’t use them unless you are consuming dietary fat. Cutting out too much fat means your body won’t be able to absorb these important nutrients.
Mental Health Risks
Dietary fat is important for brain health and development. In particular, some research has shown that fatty acids from unsaturated fats might protect against depression.
“Low-fat diet” is a broad term and advice has changed over the years, making it difficult to compare one plan to another.
Guidelines from the government and the AHA no longer specify a low-fat diet, but still recommend severely limiting saturated fats and using low-fat dairy products. Many experts now recognize other diets, such as theDietary Approaches to Stop Hypertension (DASH) diet, as heart-healthy choices.
USDA Recommendations
In December 2020, the Dietary Guidelines Advisory Committee (the group that reviews nutritional science every five years on behalf of the U.S. government), published its latest guidelines outlining the appropriate amounts of daily nutritional intake, including fats, for people across different life stages.
Similar Diets
Proponents of Ornish-type diets correctly claim that the studies that have failed to show a benefit with AHA-type diets do not necessarily apply to their far more fat-restrictive diets. However, the claims that Ornish-type diets are proven effective are themselves based on imperfect data that does not hold up well to objective scrutiny.
The hypothesis that a very-low-fatvegetariandiet prevents or reverses heart disease has been neither convincingly proven nor disproven, although it is a hypothesis that deserves more study.
A Word From Verywell
The recommendation that everyone should eat a low-fat diet was from the beginning based on a flawed theory, and on a conscious decision to sacrifice precision for the sake of simplifying the message.
After more than three decades of attempting to confirm that low-fat diets reduce heart disease, clinical trials didnotsupport longstanding recommendations that everyone should be on a fat-restricted diet
If you are looking to lose weight, consult your healthcare provider to help design a plan that works for you. For heart health, consider the Mediterranean or DASH diets.
6 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.U.S. Department of Agriculture and U.S. Department of Health and Human Services.History of theDietary Guidelines.Bhandari P, Sapra A.Low Fat Diet.In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing.Tobias DK, Chen M, Manson JE, Ludwig DS, Willett W, Hu FB.Effect of low-fat diet interventions versus other diet interventions on long-term weight change in adults: a systematic review and meta-analysis.Lancet Diabetes Endocrinol. 2015;3(12):968-79. doi:10.1016/S2213-8587(15)00367-8Shan Z, Guo Y, Hu FB, Liu L, Qi Q.Association of Low-Carbohydrate and Low-Fat Diets With Mortality Among US Adults.JAMA Intern Med. 2020 Apr 1;180(4):513-523. doi: 10.1001/jamainternmed.2019.6980.Sánchez-Villegas A, Verberne L, De Irala J, et al.Dietary Fat Intake and the Risk of Depression: The SUN Project.PLoS One. 2011;6(1):e16268. doi:10.1371/journal.pone.0016268U.S. Department of Agriculture and U.S. Department of Health and Human Services.Dietary Guidelines for Americans, 2020-2025. 9th Edition.Additional ReadingVannice G, Rasmussen H.Position of the academy of nutrition and dietetics: dietary fatty acids for healthy adults. JAcad Nutr Diet. 2014;114(1):136-53. doi:10.1016/j.jand.2013.11.001
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.U.S. Department of Agriculture and U.S. Department of Health and Human Services.History of theDietary Guidelines.Bhandari P, Sapra A.Low Fat Diet.In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing.Tobias DK, Chen M, Manson JE, Ludwig DS, Willett W, Hu FB.Effect of low-fat diet interventions versus other diet interventions on long-term weight change in adults: a systematic review and meta-analysis.Lancet Diabetes Endocrinol. 2015;3(12):968-79. doi:10.1016/S2213-8587(15)00367-8Shan Z, Guo Y, Hu FB, Liu L, Qi Q.Association of Low-Carbohydrate and Low-Fat Diets With Mortality Among US Adults.JAMA Intern Med. 2020 Apr 1;180(4):513-523. doi: 10.1001/jamainternmed.2019.6980.Sánchez-Villegas A, Verberne L, De Irala J, et al.Dietary Fat Intake and the Risk of Depression: The SUN Project.PLoS One. 2011;6(1):e16268. doi:10.1371/journal.pone.0016268U.S. Department of Agriculture and U.S. Department of Health and Human Services.Dietary Guidelines for Americans, 2020-2025. 9th Edition.Additional ReadingVannice G, Rasmussen H.Position of the academy of nutrition and dietetics: dietary fatty acids for healthy adults. JAcad Nutr Diet. 2014;114(1):136-53. doi:10.1016/j.jand.2013.11.001
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
U.S. Department of Agriculture and U.S. Department of Health and Human Services.History of theDietary Guidelines.Bhandari P, Sapra A.Low Fat Diet.In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing.Tobias DK, Chen M, Manson JE, Ludwig DS, Willett W, Hu FB.Effect of low-fat diet interventions versus other diet interventions on long-term weight change in adults: a systematic review and meta-analysis.Lancet Diabetes Endocrinol. 2015;3(12):968-79. doi:10.1016/S2213-8587(15)00367-8Shan Z, Guo Y, Hu FB, Liu L, Qi Q.Association of Low-Carbohydrate and Low-Fat Diets With Mortality Among US Adults.JAMA Intern Med. 2020 Apr 1;180(4):513-523. doi: 10.1001/jamainternmed.2019.6980.Sánchez-Villegas A, Verberne L, De Irala J, et al.Dietary Fat Intake and the Risk of Depression: The SUN Project.PLoS One. 2011;6(1):e16268. doi:10.1371/journal.pone.0016268U.S. Department of Agriculture and U.S. Department of Health and Human Services.Dietary Guidelines for Americans, 2020-2025. 9th Edition.
U.S. Department of Agriculture and U.S. Department of Health and Human Services.History of theDietary Guidelines.
Bhandari P, Sapra A.Low Fat Diet.In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing.
Tobias DK, Chen M, Manson JE, Ludwig DS, Willett W, Hu FB.Effect of low-fat diet interventions versus other diet interventions on long-term weight change in adults: a systematic review and meta-analysis.Lancet Diabetes Endocrinol. 2015;3(12):968-79. doi:10.1016/S2213-8587(15)00367-8
Shan Z, Guo Y, Hu FB, Liu L, Qi Q.Association of Low-Carbohydrate and Low-Fat Diets With Mortality Among US Adults.JAMA Intern Med. 2020 Apr 1;180(4):513-523. doi: 10.1001/jamainternmed.2019.6980.
Sánchez-Villegas A, Verberne L, De Irala J, et al.Dietary Fat Intake and the Risk of Depression: The SUN Project.PLoS One. 2011;6(1):e16268. doi:10.1371/journal.pone.0016268
U.S. Department of Agriculture and U.S. Department of Health and Human Services.Dietary Guidelines for Americans, 2020-2025. 9th Edition.
Vannice G, Rasmussen H.Position of the academy of nutrition and dietetics: dietary fatty acids for healthy adults. JAcad Nutr Diet. 2014;114(1):136-53. doi:10.1016/j.jand.2013.11.001
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