Don't be hostile to fat! Understand the Types of Good Fats, Safe Limits, and Their Effects on the Body

For decades, the word "fat" has carried a bad reputation in the world of dieting. Many people believe that to live healthy and get an ideal body, all fat intake needs to be cut out entirely. In reality, eliminating fat from your plate too drastically can actually harm your health.

Fat is one of the three main macronutrients (alongside protein and carbohydrates) that the body genuinely needs. The key isn't avoiding fat altogether, but understanding which types of fat to eat and which ones to avoid.

1. Why Does Our Body Need Fat So Much?

Fat isn't just an energy reserve. Physiologically, it carries out vital functions that no other nutrient can replace:

• Absorbing Crucial Vitamins: Vitamins A, D, E, and K are fat-soluble. Without enough fat, the body can't absorb these important vitamins optimally.
• Protecting Brain and Nerve Health: About 60% of human brain tissue is made up of fat. Fat forms the myelin sheath that insulates nerve fibers, allowing brain signals to travel quickly and efficiently.
• Raw Material for Hormones: Fat is needed for synthesizing vital hormones, including reproductive hormones (estrogen and testosterone) and stress-regulating hormones.
• Organ Cushioning and Body Temperature Protection: Visceral and subcutaneous fat serve as physical protection for internal organs against impact and help keep body temperature stable.

2. Distinguishing Fat: Which to Eat vs. Which to Avoid?

Not all fats are created equal. Generally, fat falls into a few main categories:

A. Highly Recommended Fat (Healthy Fats)

Monounsaturated Fatty Acids (MUFA):

Benefit: Helps lower bad cholesterol (LDL) while maintaining good cholesterol (HDL) levels and improving insulin sensitivity.

Best sources: Avocado, extra virgin olive oil, almonds, cashews, and seeds.

Polyunsaturated Fatty Acids (PUFA, including Omega-3 and Omega-6):

Benefit: Reduces systemic inflammation, supports heart blood vessel health, and supports brain cognitive function.

Best sources: Fatty fish (salmon, sardines, mackerel), chia seeds, flaxseeds, and walnuts.

B. Fat That Needs to Be Limited

Saturated Fats:

Effect: When eaten in excess, saturated fat can raise LDL levels in the blood, which risks triggering plaque buildup in blood vessels (atherosclerosis).

Sources: Fatty red meat, chicken skin, butter, cheese, and palm oil. This fat isn't entirely off-limits, but portions need to be tightly controlled.

C. Fat That Must Be Avoided Entirely

Trans Fats (Partially Hydrogenated Oils):

Effect: This is the most dangerous type of fat. Trans fat has been clinically shown to raise LDL cholesterol while lowering HDL cholesterol, trigger blood vessel inflammation, and drastically increase the risk of coronary heart disease.

Sources: Factory-processed food, packaged biscuits, deep-fried food, and hard liquid margarine.

3. How Much Fat Do You Need, and What's the Daily Limit?

Based on guidance from global health institutions and nutrition expert organizations:

• Total Daily Need: The World Health Organization (WHO) and Dietary Guidelines for Americans recommend that 20% to 35% of your total daily calories come from fat.
• Example Calculation: If your daily calorie need is 2,000 calories, your ideal fat intake is 44 to 77 grams per day (since 1 gram of fat equals 9 calories).
• Maximum Saturated Fat Limit: WHO recommends saturated fat intake not exceed 10% of total daily calories (a maximum of around 22 grams per day for a 2,000-calorie diet). For individuals with a history of heart disease, the American Heart Association (AHA) suggests a stricter limit of 5%–6% (around 11–13 grams per day).
• Maximum Trans Fat Limit: WHO sets the maximum trans fat limit at less than 1% of total calories (less than 2.2 grams per day), and strongly recommends avoiding it entirely (zero intake).

Conclusion

Eating a healthy diet doesn't mean waging war on and eliminating all types of fat. The real key lies in choosing the right type of fat. Replace excess saturated fat and trans fat sources with whole unsaturated fats rich in nutrients, like avocado, nuts, seeds, and olive oil. By eating good fat in the right portions, your body will actually become more energetic, your brain more focused, and your heart's health well protected.

Scientific References

World Health Organization. (2023). Healthy diet: Fact sheet N°394. Geneva: World Health Organization.

Sacks, F. M., et al. (2017). Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association. Circulation, 136(3), e1-e23.

Calder, P. C. (2015). Functional Roles of Fatty Acids and Their Effects on Human Health. JPEN. Journal of Parenteral and Enteral Nutrition, 39(1_suppl), 18S-32S.

Mozaffarian, D., Katan, M. B., Ascherio, A., Stampfer, M. J., & Willett, W. C. (2006). Trans Fatty Acids and Cardiovascular Disease. New England Journal of Medicine, 354(15), 1601-1613.