Fat has been given a bad rap over the years, being blamed for everything from obesity and heart disease to diabetes and cancer. But fat is actually an important part of a healthy diet. The key is to eat the right type of fat and to consume it in moderation. Some fats provide your body with essential fatty acids, promote absorption of fat-soluble vitamins and provide you with energy, while others can cause inflammation and lead to blockages in your arteries.

One reason for the push for lowering fat intake in the past is that dietary fat is calorie-dense and can lead to obesity – and obesity can contribute to a number of health issues. One gram of fat contains 9 calories, while one gram of carbohydrates or protein has only 4 calories. While you still need to limit the amount of fat you consume if you’re trying to lose or manage weight, your body needs some fat to function. Choose wisely and your body will reap the rewards of the fat calories you consume.

According to the most recent 2015-2020 Dietary Guidelines, a healthy eating plan can contain up to 35% of total daily calories from fat, but this should be comprised primarily of unsaturated fats. The guidelines recommend saturated fat be no more than 10% of total daily calories. Research shows that eating more saturated fat raises the risk of early death. Trans-fat is the most harmful type of fat and should be kept to a minimum or avoided altogether. Trans-fats have been linked to higher LDL cholesterol, lower HDL cholesterol and an increased risk of heart disease and stroke.

It’s important to realize that many foods don’t contain just one type of fat, but rather multiple fat types in the same food. The predominant type of fat any particular food contains is most important but the amount of all types of fat in the foods you eat shouldn’t be overlooked because everything adds up throughout the day.

Here’s the skinny on good fats vs. bad fats so you can maximize the health benefits of the fat you eat. Keep in mind that all fats, whether good or bad, contain 9 calories per gram. Those calories can really add up quickly so pay attention to how much total fat you include in your diet.

“GOOD” Fats

Unsaturated fats – This includes both monounsaturated and polyunsaturated fats. When eaten in moderation, unsaturated fats help lower your risk of heart disease and reduce cholesterol levels. Unsaturated fats are liquid at room temperature.

Good sources include:

  • Monounsaturated fats
    • Avocado
    • Nuts and seeds
    • Olive, canola and peanut oils
  • Polyunsaturated fats (includes omega-3 and omega-6 fatty acids)
    • Cold-water fish (salmon, mackerel, trout, sardines)
    • Flaxseeds
    • Corn, sunflower or safflower oils

“BAD” Fats

Saturated and trans-fats – These can increase your risk of heart disease by raising harmful LDL cholesterol and lowering beneficial HDL cholesterol. Trans-fats have been shown to increase inflammation in the body and can contribute to insulin resistance, which may lead to heart disease, stroke, diabetes and other chronic conditions. Saturated fats are solid at room temperature.

Primary sources include:

  • Saturated fats
    • Animal-based fats (from dairy, meat, poultry and eggs)
    • Vegetable fats that are solid at room temperature (coconut and palm oils)
    • Butter and lard
  • Trans-fats – hydrogenated or partially-hydrogenated oils found in processed foods, including:
    • Fried foods
    • Baked goods and packaged snack foods (cookies, cakes, crackers)
    • Margarine and vegetable shortening

To get an idea of how much of each type of fat various foods contain, here is one example from each section listed above:

Food – Serving Size Total Fat Monounsaturated Fat Polyunsaturated Fat Saturated Fat Trans Fat
Avocado – 1 cup 21g (32%DV) 14g 2.7g 3.1g (15% DV)
Salmon – ½ fillet 27g (41%) 7g 8g 6g (30%)
Butter – 1 T 12g (18%) 3g 0.4g 7g (35%)
Margarine – 1T 11g (16%) 6g 3.5g 2.2g (11%) 2.1g

Healthy fats are an important part of your diet but should be consumed in moderation due to their high calorie content. Whenever possible, opt for mostly “good” fats and avoid “bad” fats as much as possible.

Sources:

https://www.choosemyplate.gov/2015-2020-dietary-guidelines-answers-your-questions

https://www.ncbi.nlm.nih.gov/pubmedhealth/behindtheheadlines/news/2016-07-06-study-finds-link-between-saturated-fats-and-early-death/

http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Nutrition/Trans-Fats_UCM_301120_Article.jsp#.WJaNd4WcH4g

http://www.webmd.com/diet/obesity/features/skinny-fat-good-fats-bad-fats#1

http://www.health.harvard.edu/staying-healthy/the-truth-about-fats-bad-and-good

http://www.healthline.com/health/heart-disease/good-fats-vs-bad-fats