Does Fat Intake Cause Muscle Growth?

Eating fats is important for absorbing vitamins.
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Physical strength and muscle growth are important in many competitive sports. Macronutrients all play a role in optimizing muscle and, although eating fat for muscle gain cannot directly build muscle, dietary fat plays a huge role in developing body composition and increasing athletic performance.

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Consuming fats is important for absorbing essential vitamins, and producing energy and hormones necessary for muscle growth.

Role of Fat in Muscle Building

To build muscle, you need to eat a variety of nutrient-dense foods with the right blend of proteins, carbohydrates and healthy fats. The correct combination of these macros for muscle gain for female and male athletes is important to provide energy for muscle contractions and to sustain the physical activity needed for exercise.


Fat in your diet has an influential role in maintaining optimal cell structure and hormone levels, both of which are crucial for supporting a muscle-building environment. Fat is required to protect cell membranes, the vital exterior of every cell, and sheaths surrounding nerves, says Harvard Health Publishing. Dietary fat is also essential for muscle movement, blood clotting and inflammatory response, which helps the body repair from injury during intensive training.

All kinds of fats have over twice the energy when compared to carbs and protein. Dietary fats provide nine calories per gram while carbohydrates and proteins each provide four calories per gram, according to the American Heart Association. Fat ingested as food is synthesized by oxidation and broken down into fatty acids, which are transported via the bloodstream to fuel your muscles during your training sessions.


Read more: Your Ultimate Guide to Gaining Lean Muscle

Muscle-Building Vitamins Need Fat

In addition to providing energy necessary for proper metabolic function, fat also facilitates the absorption of fat-soluble vitamins. These micronutrients include vitamins A, D, E and K, which all have a role in building and maintaining muscle.

Vitamin A is well-known for its benefit for vision, but it is also particularly important as an antioxidant, especially during endurance training, says the Academy of Nutrition and Dietetics. Fat-soluble vitamin D is needed for normal muscle function — low vitamin D levels are associated with risk of falls and muscle instability, according to the June 2018 Bone Reports publication.


Vitamin E can prevent muscle atrophy and promote muscle regeneration, as demonstrated from a July 2014 study in the Oxidative Medicine and Cellular Longevity, where scientists found that a deficiency of vitamin E inhibits the healing of plasma membranes. This is important because muscle cells get membrane tears just from being used and part of how muscle is built is from the natural tearing and repair process.

Athletes use vitamin K to help recover and strengthen muscles. However, without fat in the diet to help its absorption, they may not get benefits of vitamin K, even in supplemental form. A small study published in Alternative Therapies in Health and Medicine in July 2017 reported that vitamin K2 can help restore mitochondrial function and suggested that it could increase the function of skeletal and cardiac muscle.


Eat the Right Amount of Fat

You can get all the fat you need from your diet, with both plant and animal foods. The USDA 2015-2020 Dietary Guidelines recommend that 25 to 35 percent of your total calories should come from fat for long-term health. However, many athletes, including bodybuilders who strive for lean muscle, often restrict fat intake in an attempt to lose weight. This practice may have unhealthy consequences on your body.

The Medicine & Science in Sports & Exercise (MSSE) published a position statement in March 2016 that discouraged consuming less than 20 percent of calories from fat. Reducing fat intake would likely reduce the ingestion of a variety of nutrients, including vitamins and essential fatty acids. A long-term low-fat diet, and the resulting decrease in overall calories, can put you at risk for low energy availability.

If your calorie intake is insufficient to adequately support all the physiological functions needed to meet the demands of training, consequences can include low muscle mass, hormonal disruption, inadequate bone density, increased fatigue, injury and illness and prolonged recovery, according to MSSE.

In addition, a deficiency of fat in your diet may cause acute skin conditions, increased susceptibility to infection and poor healing which could affect the repair of muscles, according to the Linus Pauling Institute.

Read more: Your Ultimate Guide to Fats and Why Your Diet Needs Them

How Fat Affects Testosterone

Fat has a bidirectional influence on male and female sex hormones, according to an August 2013 article published in the World Journal of Men's Health. The article reported an increased level of testosterone in the bloodstream showed a decline in the risk of heart disease and had a negative correlation with obesity. Hormones play a significant role in maintaining and enhancing muscle mass and strength as well as protecting against muscle damage, says the National Institute of Health.

As you get older, it's harder to build and maintain muscle. The Academy of Nutrition and Dietetics says most people start losing muscle around age 30. Being physically inactive can cause between 3 and 5 percent loss of lean muscle mass every decade thereafter. This muscle loss may be due to lower testosterone and estrogen levels, present in both men and women. Maintaining an adequate level of fat in your diet can help produce and release hormones that contribute to muscle retention.

According to the May 2014 review of scientific literature, published in the Journal of the International Society of Sports Nutrition, significantly restricting fat intake may result in reductions in testosterone levels that could impair hormonal response, which is important in both male and female athletes. Collective data from the review indicated that when extremely lean body compositions are attained through aggressive dieting, the caloric deficit and loss of body fat may have a large impact on testosterone levels.

Fat for Muscle Gain

Fat is not all created equal and it's important to understanding the different types of fat and know which ones to include in your healthy diet for muscle-building foods. Although most foods contain a combination of different types of fat, fatty acids are primarily divided into unsaturated fat, which includes poly- and monounsaturated fat, saturated and trans fats.

Unsaturated fat is the healthiest type of fat. It is the kind of fat found in plant-based foods and oils. Foods containing mostly mono- and polyunsaturated fats are known to improve blood cholesterol levels, which can reduce your risk of heart attacks and type 2 diabetes, according to the Mayo Clinic.

Omega-3 is a specific type of monounsaturated fat that is essential for brain function and cell growth, including your muscles. Omega-3 fatty acids include ALA (alpha-linolenic acid), EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Researchers have found that EPA and DHA have a positive role in muscle building.

A September 2019 review, published in Frontiers in Nutrition, reported that the potential positive influence on skeletal muscle, gains in muscle size and muscle strength from omega-3s may be due to enhancement of muscle protein synthesis by EPA and DHA. These omega-3 fatty acids help regulate muscle breakdown and improve conversion of energy within mitochondria.

The review says intake of omega-3 fatty acid not only alleviates the loss of muscle mass in older people, it protects against muscle loss during muscle-disuse.

Limit Your Saturated Fat Intake

Saturated fats are found naturally in animal products such as meat, chicken and dairy products, and also in some tropical oils and nuts. While there's no need to cut out all saturated fat from your diet, the Dietary Guidelines recommend limiting the consumption of saturated fat to 10 percent of your daily calories and replacing that fat with healthy unsaturated fats instead of refined carbs.

In July 2014, a small trial published in the Diabetes journal concluded that gaining weight from excessive intake of polyunsaturated fat appears to cause more gain in muscle mass and less body fat compared to eating a similar amount of saturated fat. Researchers suggested polyunsaturated fatty acids can have a more favorable effect on fat distribution in the body than saturated fats by increasing energy or decreasing the storage of visceral fat.

Trans fats are naturally found in small amounts in meat and dairy products. At levels consumed in a diet low in saturated fat, the American Heart Association claims insufficient evidence that naturally occurring trans fats in food have the same bad effects on cholesterol as hydrogenated vegetable fats and oils.

However man-made trans fats, such as found in commercially baked goods, pose a high health risk. If you are training to build muscle, be sure to read labels carefully to make sure you are eating fats that will support your health the most and avoid partially hydrogenated-processed foods.

Benefit from Medium-Chain Triglycerides

Recently, medium-chain triglycerides, or MCTs, have become popular with athletes and bodybuilders for their fat-burning potential and energy sustaining powers. But does MCT oil really contain essential healthy fats that help with muscle growth?

According to the Nutrition Review published in April 2013, MCTs are absorbed and metabolized more rapidly than other fats containing long chain triglycerides (LCT), such as olive oil, nuts and avocados. This accelerated metabolic process results in a quicker conversion to energy needed to fuel muscles, with less fat being stored in adipose tissue. Although MCTs have fewer calories per gram than LCTs, they both contain a high amount of unhealthy saturated fat.

Natural sources of MCTs include coconut oil and palm kernel oil. Although these oils may digest faster, and could benefit certain athletes, the high content of saturated fat may outweigh the benefits. For example, coconut oil contains 12 grams of saturated fat per tablespoon, which equates to 60 percent of the daily value, according to USDA.

Excessive use of MCT oil may cause intestinal distress such as diarrhea, cramping, gas, bloating and abdominal discomfort, according to the February 2017 issue of the Practical Gastroenterology. Although a meta-analysis of randomized controlled trials, published in the February 2015 Journal of the Academy of Nutrition and Dietetics, found that replacing LCTs with MCTs may have a positive influence on satiety resulting in reduced body weight, further research is suggested to confirm the effectiveness and long-term health effects of MCT oils.

Read more: List of Foods That Contain Medium-Chain Triglycerides