Why it is important to put fat in your body for good health

December 22, 2025 •

3 min read

According to the World Health Organization, fat should not exceed 30% of your total daily energy intake, highlighting its crucial, though often misunderstood, role in a healthy diet. Contrary to outdated beliefs, understanding why it is important to put fat in your body reveals its essential functions far beyond just a source of calories.

Quick Summary

Fats are a vital macronutrient, providing energy, supporting cell growth, and aiding the absorption of essential fat-soluble vitamins (A, D, E, K). They are crucial for hormone production, brain health, and managing inflammation, making quality fats a necessary part of a balanced diet for overall wellness.

Key Points

Energy Source: Fat is a dense energy source, providing 9 calories per gram, crucial for fuelling the body and providing long-lasting energy.
Vitamin Absorption: Healthy fats are essential for the absorption of fat-soluble vitamins A, D, E, and K, which are vital for vision, immunity, bone health, and blood clotting.
Cell Structure: Fats form the membranes of every cell in the body, maintaining their flexibility and function, which is critical for cell communication and overall health.
Hormone Production: Adequate fat intake is necessary for the production of vital hormones, including sex hormones and stress regulators, supporting metabolic and reproductive health.
Brain Function: The brain is 60% fat, and essential fatty acids, particularly omega-3s, are crucial for cognitive function, memory, and mood regulation.
Healthy Choices Matter: Not all fats are equal; prioritize unsaturated fats from sources like fish, nuts, and olive oil, while minimizing saturated fats and avoiding trans fats completely.
Weight Management: Despite common misconceptions, incorporating healthy fats can aid in weight management by increasing satiety and preventing overeating.

The Core Functions of Dietary Fats

For decades, fats were villainized, with low-fat diets promoted as the gold standard for health and weight management. However, modern nutritional science has revealed the critical and complex roles that fats play in the body. They are not merely an energy storage system but are fundamental to many physiological processes. Recognizing why it is important to put fat in your body is the first step toward a more balanced and healthy approach to eating. From the cellular level to systemic functions, healthy fats are indispensable.

Energy and Fuel

One of the most well-known functions of fat is its role as a concentrated energy source. Gram for gram, fat provides more than twice the energy of carbohydrates or protein, offering 9 calories per gram compared to their 4. This dense energy supply is especially important for long-duration activities and for maintaining body temperature. The body efficiently stores excess energy as fat for later use, a survival mechanism that is still vital today. This storage also serves as a crucial reserve during periods of starvation or high metabolic demand.

Essential Vitamins and Absorption

Certain vitamins—specifically vitamins A, D, E, and K—are fat-soluble, meaning they can only be absorbed and transported through the body with the help of fat. A deficiency in dietary fat can therefore lead to a deficiency in these critical vitamins, causing a cascade of health issues.

Vitamin A: Important for vision, immune function, and reproduction.
Vitamin D: Crucial for bone health, immune function, and regulating mood.
Vitamin E: A powerful antioxidant that protects cells from damage.
Vitamin K: Essential for blood clotting and bone metabolism.

Building Blocks for Cellular Health

Every cell in your body has a membrane composed primarily of a fatty layer. These membranes are not just passive barriers; their flexibility and integrity, which are largely dependent on dietary fats, are crucial for cell communication and function. Polyunsaturated fats, such as omega-3 and omega-6 fatty acids, are particularly vital for maintaining supple and functional cell membranes. Without adequate fat, cell membranes become rigid, disrupting cellular processes and overall health.

Hormone Production and Regulation

Fats are the building blocks for many hormones, including steroid hormones like estrogen, testosterone, and cortisol. A diet too low in fat can disrupt hormonal balance, leading to issues with metabolism, mood, and reproductive health. Furthermore, fat tissue itself is an active endocrine organ that produces over 50 different types of signaling molecules, including leptin, which helps regulate appetite and energy balance.

Supporting Brain and Nerve Function

The human brain is approximately 60% fat, making healthy fats non-negotiable for cognitive health. Omega-3 fatty acids, like DHA and EPA, are essential for brain development and function, affecting everything from memory and mood to fighting inflammation. A consistent supply of good fats is vital for maintaining proper nerve function and reducing the risk of cognitive decline associated with aging.

Comparison of Dietary Fat Types

Not all fats are created equal. Knowing the differences between them is key to making healthy choices. Here is a brief comparison of the main types of dietary fats:


Feature	Saturated Fats	Monounsaturated Fats (MUFAs)	Polyunsaturated Fats (PUFAs)	Trans Fats
Physical State	Solid at room temperature	Liquid at room temperature	Liquid at room temperature	Solidified through processing
Sources	Red meat, butter, cheese, coconut oil	Olive oil, avocados, nuts, peanut oil	Fatty fish, flaxseed, walnuts, sunflower oil	Margarine, processed baked goods, fried foods
Health Impact	Can raise LDL ('bad') cholesterol, increasing heart disease risk.	Can lower LDL cholesterol and raise HDL ('good') cholesterol.	Can lower LDL cholesterol and provide essential omega-3 and omega-6.	Raises LDL cholesterol and lowers HDL cholesterol, significantly increasing heart disease risk.
Recommendation	Consume in moderation.	Highly recommended; replace saturated fats.	Highly recommended; essential omega-3 and omega-6 must come from diet.	Avoid completely, especially industrially produced versions.

Conclusion

For too long, dietary fat has been unfairly blamed for health issues rooted in broader dietary imbalances. The reality is that including the right types of fat in your diet is not only safe but is absolutely crucial for your overall health. Healthy fats are needed for energy, nutrient absorption, cellular structure, hormone production, and cognitive function. The key is to move away from industrially processed trans fats and to moderate saturated fat intake, focusing instead on nutrient-dense sources of mono- and polyunsaturated fats. By doing so, you can support your body's most fundamental processes and pave the way for long-term wellness. Embracing this nutritional nuance is how we truly unlock a balanced and healthy lifestyle.

Frequently Asked Questions

Not eating enough fat can lead to several health issues, including deficiencies in fat-soluble vitamins (A, D, E, K), dry and scaly skin, hair loss, a weakened immune system, and hormonal imbalances.

According to the World Health Organization and other health bodies, total fat should constitute no more than 30% of your total daily energy intake. The focus should be on prioritizing unsaturated fats over saturated and trans fats.

Saturated fats should be consumed in moderation. While they are a building block for some hormones, excessive intake can raise LDL ('bad') cholesterol levels and increase the risk of heart disease.

The healthiest fats are unsaturated fats, which include monounsaturated and polyunsaturated fats. Good sources include avocados, nuts, seeds, olive oil, and fatty fish like salmon.

No, eating fat does not inherently make you fat. Weight gain is caused by consuming more calories than you burn, regardless of the source. Because fats are calorie-dense, overconsumption is a risk, but in moderation, healthy fats are part of a balanced diet and can promote satiety.

Essential fatty acids (EFAs) are polyunsaturated fats, specifically omega-3 and omega-6, that the body cannot produce on its own and must obtain from food. They are critical for cellular function, brain health, and inflammation regulation.

Fats are a crucial component for hormone synthesis, including sex hormones like estrogen and testosterone. A diet with healthy fats helps maintain hormonal balance and can even reduce levels of stress hormones like cortisol.