If you're old enough to remember when fats were bad — and low-fat and fat-free foods filled every pantry, cabinet, and refrigerator — the messaging today that they're an essential part of any diet and may even help you lose weight can be confusing. We spoke with a registered dietitian and nutritionist to set the record straight.
"Fats actually play really important functions in our bodies," Heather Shablin, RDN, LD, PTAG-CPT, told POPSUGAR. "Just to name a few, fats provide our bodies with energy and protect vital organs." The body also needs fat in order to absorb essential fat-soluble vitamins, including vitamins A, D, E, and K, she explained.
Making them part of your diet can even aid in weight loss. It takes more time for the body to digest fat, which keeps you feeling fuller longer, naturally reducing your calorie intake. Beyond that, eliminating fats from your diet may slow your metabolism. One study found that those who followed a low-fat diet experienced the greatest decrease in both resting and total energy expenditure following weight loss. In layman's terms, that's the number of calories burned each day.
Heather explained that the key is choosing healthy fats and cutting out unhealthy ones. There are four main types of dietary fats: monounsaturated and polyunsaturated fats (the "good" fats) and saturated and trans fats. The latter can raise your low-density lipoprotein, or bad cholesterol, putting you at greater risk for cardiovascular disease. So you have to be cautious about treating yourself to things like cookies, ice cream, chips, fried food, high-fat dairy products, and red meat.
However, it's also possible to overdo it with healthy fats like avocado, nuts, and fatty fish — just as you can overindulge on other good-for-you foods, like fruit. "Having too much healthy fat will not help you lose weight either," Heather said. "Having a well-balanced diet consisting of healthy carbs, lean protein, and healthy fats is the best way to achieve your weight loss and health goals."