Ah, fat. The loads of opinions we hear about dietary fat (and nutrition in general) are conflicting, confusing, and kind of exhausting. People ask me all the time how they’re supposed to know what to believe about nutrition in general. It took me a long time to figure that out myself, so I wrote a blog post about it. You can read it here. Now, let’s talk about fat.

Why do we need dietary fat?

Fat helps give your body energy, supports cell growth, keeps cholesterol and blood pressure under control, protects your organs, and helps your body produce important hormones and absorb vital fat-soluble nutrients.

How much dietary fat do we need?

Fat is a macronutrient, which means we need it in large quantities (large in relation to micronutrients) for the normal functioning of our body’s systems. The DRI (dietary reference intake) for fat in adults is 20-35% of your daily calories. That amounts to 44 to 77 grams of fat per day if you eat 2000 calories a day. But many argue (and I agree with them) that we actually need even less than that. About 20-30 grams a day is totally sufficient for adults if that fat is coming from healthy sources.

You’ll hear all kinds of amounts recommended. Keep in mind that the amounts can be skewed by commercial interests. So just be sure you consider the source. While fat is an essential nutrient, excess of it is not necessary or beneficial to our bodies.

Healthy dietary fat vs unhealthy dietary fat

You may believe that all fats are bad for you, but there has been a pretty big “healthy fat” push for a while now. So I’m sure you’ve probably heard otherwise at this point. The fact is, not all fats are created equal and we don’t need all fats.

Unhealthy fats:

Saturated fat and trans fat are the bad guys in the fat category. These fats are mostly solid at room temperature (picture that in your arteries) and have diverse effects on your cholesterol. Trans fat is more of a villain than saturated fat, but both can increase the risk of heart disease and stroke. Saturated fat should be majorly limited while trans fat should be avoided altogether. Saturated fat in excess raises LDL (or bad) cholesterol. Trans fat is the worst fat of all because it raises LDL cholesterol and lowers HDL (or good) cholesterol. Saturated and trans fats are viscous or have a thick, sticky consistency between solid and liquid, making them especially damaging to arteries and heart health.

Healthy fats:

Monounsaturated fats and polyunsaturated fats are the superheroes of fat. Unsaturated fats lower your risk of heart disease and stroke, lower LDL (bad) cholesterol and raise HDL (good) cholesterol, fight inflammation, lower blood pressure, and prevent atherosclerosis (narrowing of the arteries).

The power of omega-3s

Omega-3 fatty acids are a type of polyunsaturated fat and are especially beneficial to our health. There are different types of omega-3s: EPA and DHA are found in fish and algae and have the most health benefits, while ALA comes from plants. ALA is a less potent form of omega-3, but it is still beneficial and sufficient if you do not consume animal products. The body does convert ALA to EPA and DHA at low rates, but that does not negate the effectiveness of ALA.

Research indicates that a diet rich in omega-3s may help to:

  • Prevent fatigue, improve memory, and balance your mood.
  • Protect against memory loss and dementia.
  • Reduce the risk of heart disease, stroke, and cancer.
  • Reduce arthritis, joint pain, and inflammatory skin conditions.
  • Support a healthy pregnancy.
  • Prevent and reduce symptoms of depression, ADHD, and bipolar disorder.

The Best Sources of Omega-3s

Fish (High in EPA and DHA)

  • Anchovies
  • Herring
  • Salmon
  • Mackerel
  • Sardines
  • Trout
  • Tuna
  • Mussels
  • Oysters
  • Halibut

Vegetarian Sources (High in ALA)

  • Algae such as seaweed (high in EPA and DHA)
  • Eggs (small amounts of DHA)
  • Flaxseeds and flaxseed oil
  • Chia seeds
  • Canola and soybean oil
  • Walnuts
  • Mayonnaise
  • Edamame
  • Beans (refried, kidney, etc.)
  • Brussels sprouts
  • Kale
  • Spinach

Dietary fat and cholesterol

A quick lesson in cholesterol is necessary to explain why it’s important that we avoid both trans and saturated fats. Cholesterol is a type of blood fat (or lipid). Our bodies need cholesterol to build the structure of cell membranes, make hormones like estrogen, testosterone, and adrenal hormones, help our metabolism work efficiently, and more. The amount we need is very small and our livers happen to make all the cholesterol we need all on their own.

  • HDL cholesterol is the “good” cholesterol found in your blood.
  • LDL cholesterol is the “bad” kind.
  • To protect against heart disease and stroke, we need to keep LDL cholesterol low and HDL cholesterol high.
  • High levels of LDL cholesterol can clog arteries and low HDL can put you at higher cardiovascular risk.

Dietary fat plays a major role in our cholesterol levels. In fact, it’s not the actual amount of cholesterol in your diet but the type of fats you consume that influence your cholesterol levels the most. That’s why it’s important to replace unhealthy fats with healthy fats.

Should you eat a low-fat diet?

I recommend a low-fat diet of 20-30 grams per day. This will help you maintain a healthy weight and still get sufficient amounts of fat in your diet. Many will disagree with me, and many will agree with me. Again, I can’t say this enough, you should make your own decision with some research outside of this blog post. I will say that based on all of the information I’ve researched, 20-30 grams of healthy fat is sufficient for maintaining healthy physical and mental health. Remember that unhealthy fats may have some of the benefits of healthy fats, but they come with all the issues discussed above when consumed excessively.

What about oils?

Oils are a highly disputed topic. I won’t go too deep into the oil argument here because most of the information about the health benefits of oil are true. Mainly regarding extra virgin olive oil. What isn’t often discussed is the negative effects that oil can have on our weight, which can eventually have negative effects on our health.

Oils are the most calorically dense food items on the planet. Calorie density is simply a measure of how many calories are in a given weight of food, most often expressed as calories per pound.

Here are a few examples:

  • 1 lb of meat – 1000 calories
  • 1lb of veggies – 100 calories
  • 1lb of cheese – 1700 calories
  • 1lb of grains – 500 calories
  • 1lb of oils – 4000 calories

This concept matters for weight loss and maintenance because the most successful approach to weight loss is to consume the same volume of food you’re used to, but make sure that volume is made up of less calorie-dense food. So instead of eating less food, you’re eating the same amount of food but fewer calories.

Oils undermine this concept because it is easy to overuse them and end up drastically increasing your calorie intake for the day with very little to show for it. Oil has zero capability of satiating your hunger. Meaning that 40 calories in one teaspoon of oil used while cooking does not fill you up at all. It’s only flavoring and mildly so at one teaspoon. Studies show that most people use around 1-2 tablespoons of extra virgin olive oil to cook with at each meal. That’s an additional 125 to 250 calories per meal. You could eat an entire pound of vegetables for fewer calories than one tablespoon of olive oil.

Excessive Use of Oils vs Moderation

If you drizzle a little olive oil for cooking, that can be easily managed. But then there are some recipes that call for measurements like 1/4 cup of olive oil! That’s around 475 calories of just oil in your food. So while olive oil may have health benefits, used this way they are also adding to your troubles if you are attempting to lose weight or maintain weight loss.

I’m not necessarily saying that you should remove oil from your diet entirely, but it would not hurt you to do so if you are getting healthy fat from other plant sources. If you do use it, be sure to be very mindful of the amounts you use if you are trying to lose weight.