Your body needs those good fats to absorb a whole slew of healthy vitamins. Otherwise, you could be missing out.

By By Abbey Sharp, R.D., Abbey's Kitchen
July 14, 2017
Photo: Abbey's Kitchen

Nuts, seeds, and avocados are great sources of healthy fats that everyone should be incorporating into their diets. And while if you overdo it on fat in general, or particularly the unhealthy varieties (e.g., salad dressings) can easily double the calories in your meal, a mindful portion of fat is actually imperative for more reasons than just the benefits of the fat itself. Healthy fats can actually help you get the most nutrient bang for your caloric buck, too.

Why? There are two types of vitamins out there: water-soluble and fat-soluble vitamins. Most vitamins (such as vitamin C and all of your B vitamins) are water-soluble, and therefore are just peed out when consumed in excess. But vitamins A, D, E, and K are considered fat-soluble and get stored longer in the liver and in fat. So while you need to take in vitamin C and other water-soluble vitamins regularly, your body hangs onto fat-soluble vitamins longer. (That all-inclusive weeklong trip to Mexico may provide your body with enough vitamin D to last you for weeks!)

Fat-soluble vitamins do exactly what it sounds like-they dissolve in a source of dietary fat and are carried through the intestines, into the bloodstream, and then into the liver until they're needed. But that's where you have to be careful. In order to fully reap the benefits of vitamins A, D, E, and K, your diet needs to contain enough healthy fats to carry these vitamins throughout your body. Consuming these vitamins without enough fat is like putting gas in the car but not having anyone in the driver's seat. You're not going to get anywhere with that full tank of gas (i.e. your big bowl of greens) without a designated driver (~fat!).

The fix, of course, isn't chasing down your smoothie with a box of deep-fried doughnuts. Alternatively, research suggests that vitamin absorption is actually best with a low to moderate amount of fat (around 15 to 30 grams) compared with no fat or a very fatty meal (over 35 grams). So that means about an ounce of nuts, a tablespoon of olive oil, or 1/3 of an avocado. It's also best to limit saturated fats from animal sources and avoid trans fats, and instead sticking with foods high in polyunsaturated and monounsaturated fats like olive oil, avocado, nuts, seeds, flax, fish, and chia.

Want some inspiration? Here are some of my go-to combinations. While there's no strong evidence to say a specific fat helps any more than another, sneaking in a slew of different unsaturated sources provides variety-a key aspect of a healthy diet.