For years, dietary fat was viewed as something to avoid. But while some types of fat can negatively impact health when consumed in excess, others are essential for optimal function and overall well-being. Not all fats are created equal, and some are not just acceptable but necessary for optimal health.
What Does Fat Do in the Human Body?
Fat serves a wide range of critical functions, including:
- Providing a tightly packaged, efficient storage form of energy
- Supplying essential fatty acids that are vital for brain and nervous system health and functioning
- Absorbs fat-soluble vitamins (A, D, E, and K) and transports them throughout the body
- Insulating and protecting vital organs
- Enhancing the flavor and palatability of food
- Promoting satiety (the feeling of fullness after eating)
- Supporting cell membrane function by regulating the flow of contents in and out of cells
- Serving as a building block for steroid hormones, including testosterone and estrogen, via cholesterol, which the body requires in appropriate amounts
What Are Fats, Exactly?
Most of the fat we eat comes in the form of triglycerides, which are made up of fatty acids attached to a glycerol molecule. The structure of those fatty acids determines the type of fat and how it behaves in the body.
Saturated fats have only single bonds in their fatty acid tails, while unsaturated fats contain one or more double bonds. Unsaturated fats can be further broken down into two categories: monounsaturated fatty acids (MUFAs), which have one double bond, and polyunsaturated fatty acids (PUFAs), which have multiple double bonds. The type of bonding matters because it directly affects how a fat interacts with and influences body processes.
Polyunsaturated Fatty Acids (PUFAs)
PUFAs are considered essential fats because the human body cannot produce them on its own. They must come from your diet. This category of fat has consistently shown beneficial effects on the body, playing key roles in muscle contraction and relaxation, blood vessel dilation and constriction, blood clot formation, blood lipid regulation, and immune response.
The two primary PUFAs we need are omega-3 and omega-6 fatty acids. Most Americans consume adequate amounts of omega-6 fatty acids, which are found in many commonly used vegetable oils and processed foods.
Getting enough omega-3, however, requires a bit more intention. Common sources include fatty fish, marine algae, and products derived from them. The good news is that just two servings of omega-3-rich fish per week are enough for most adults to meet their daily requirements. Because omega-3 fatty acids are incorporated into body tissues, most people can meet their needs through a few servings of fatty fish each week rather than needing a dietary source every day.
How Much Fat Should I Consume?
In general, 20–35% of your total daily calories can come from fat. Prioritizing unsaturated fats, especially polyunsaturated fats, while limiting saturated fat intake is generally recommended for overall health.
Calculating omega-3 intake is a bit more nuanced, as the recommendation is based on the amount of eicosanoids (signaling compounds derived from fatty acids) in a food source, rather than fat calories alone. This means you'll want to check the specific eicosanoid content of foods you regularly eat.
Do I Have to Eat Only Polyunsaturated Fats?
Not at all. You can enjoy other forms of fat as part of a balanced diet, as long as you stay within your overall caloric goals. The key is to make sure that a substantial portion of your fat intake comes from polyunsaturated sources. Think of it as a foundation, not a restriction. Build your fat intake around PUFAs, and there's room for other fats too.
Want More Personalized Guidance?
Nutrition can feel confusing, especially when it seems like every week there's a new headline telling you what you should or shouldn't eat. While general recommendations can be helpful, your nutrition needs are ultimately unique to your goals, lifestyle, preferences, and health history.
If you're looking for individualized guidance and support, I'd love to help. Through 1:1 coaching, I work with clients to build sustainable nutrition and training habits that fit their lives and help them make meaningful progress toward their goals.
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