Why do we need fat and which is better?  Butter or margarine?  Olive oil or coconut oil?

February 2017: the written content below has been updated to reflect new research relevant to this article.

You might be wondering if it is time for an oil change with all the latest hype about coconut oil.  You might also be curious about the current opinion on the lengthy debate about butter versus margarine.

Here are some things to think about when it comes to choosing fats and oils in your diet:

1.  Why do we need dietary fat?

With so much in the media about eating less fat overall this three-letter word has an overall negative connotation for many people.  It is important to note that fat is an essential nutrient.  It is necessary for essential fatty acids for our brain and cells in the body.  Fat is necessary to help us absorb fat-soluble vitamins such as vitamin A, D, E and K. Fat also makes food tasty, as well as keeps you from getting hungry for a longer time between meals because it is digested slowly.

If you do not have enough fat in your diet you will lack satiety in your meals and feel hungry often.

2.  Does fat in food get stored as body fat?

There is a common misconception I hear from our clients.  Just because you eat fat in food does not mean it will get stored as body fat.  Consuming an excess of calories greater than your body needs from any nutrient (carbohydrate, protein or fat) will get stored as body fat.  Ironically you could eat a diet that is very high in fat (for example consuming large amounts of ice cream) and actually lose weight if the calories you consume are reduced.

Note that body fat is also essential and having too little of it is as damaging as having an excessive amount of body fat.  Body fat is needed for energy metabolism, keeping us warm and to cushion our organs, feet and other parts of the body to protect against injury.  For women having enough body fat is essential for fertility, a healthy pregnancy and providing us with an attractive curvaceous figure.

3.  How much dietary fat should we eat per day?

The amount of dietary fat you need per day is based on a percentage of total calories. You may have heard in the media that less than 30% of your calories should come from dietary fat – in fact this is an average and there is a range. The following chart suggests the goals for the percentage of total calories recommended from dietary fat based on age.

*Based on the goals for percentage of daily calories suggested by the Dietary Reference Intakes. Acceptable Macronutrient Distribution Ranges. Food and Nutrition Board, Institute of Medicine, National Academies. 2005.

If you are curious how many grams of fat you need per day based on the above percentage goals a moderately active female adult that needs 1800-2100 calories per day would require 40-82 grams of dietary fat per day. A moderately active male adult that needs 2400-2700 calories per day would require 53-107 grams of dietary fat per day.

4.  What are the best and worst dietary fats to consume? 

The Good

Unsaturated fats (polyunsaturated and monounsaturated fats) found in vegetable oils such as olive oil, nuts, seeds, avocados and fish are healthy fats that are good for us. Be sure to include a moderate amount of these in your diet, as they lower your “bad” or LDL-cholesterol. 

One type of polyunsaturated fat known as the omega-3 fats improve heart health by making the blood less sticky, which reduces the risk of heart attack and stroke. Omega-3 fats also lower blood pressure and blood triglyceride levels and are helpful for immune and inflammatory based issues. Omega-3 fats are important for pregnant women for brain and nervous system development of babies. The best sources of omega-3 fats are fatty fish and other sources include ground flax seeds, walnuts and hemp seeds.

The Potentially Bad

Traditionally it was thought that saturated fat was harmful for heart health.  Saturated fats are found in heavily marbled meats, the skin on poultry, butter, margarine, tropical oils (coconut oil, palm oil, cocoa butter), and high fat-dairy foods such as cheese.  Newer research has found that saturated fats may or may not increase the ‘bad’ LDL-cholesterol in the body, which harms heart health. Part of the reason that there may be some conflicting results depends on which foods are being replaced for saturated fat.  Monounsaturated fats (found in olive oil, nuts and avocado) as well as omega-3 fats (found in fish) when replaced for saturated fat is beneficial for heart health.  Health depends on the quality of your whole diet, not just the type of fat or any other single nutrient.  Rather than focusing on counting grams of fat, focus first on eating wholesome foods your grandmother would recognize that contain simple ingredients.

The Ugly

Trans fats (shortening, hydrogenated vegetable oils) are found in some margarines and some packaged foods such as cookies, cakes, frozen meals, deep fried foods, and fast foods. The food label can help you determine how much trans fats are in a particular food. Aim to reduce or even eliminate trans fats from your diet since they not only increase the “bad” LDL-cholesterol but they also reduce the “good” HDL-cholesterol in our body. Trans fats also increase blood vessel inflammation that increases the risk of other chronic conditions.

5. Which is better butter or margarine?

How you answer this question depends on a few factors.  Firstly from a taste preference most chefs and foodies would agree that nothing beats butter.  Other butter advocates would say they prefer to consume something more natural. 

On the other hand vegetarians that do not consume animal foods may choose margarine instead because it is plant based.  Since soft-tub non-hydrogenated margarine is lower in saturated fat than butter and is trans fat free if you have high cholesterol you might choose this for a nutrition reason. Skip square cubes of margarine and tub hydrogenated margarines since these are high in trans fats.

At the end of the day whatever you choose be mindful of simply eating less of both.

6.  Which is better coconut oil or olive oil?

Coconut oil is all the rage lately but I don’t believe this is a fat you should be trying to increase in your diet. 

Coconut oil (which is solid at room temperature) contains a high level of saturated fats (more than butter).  One positive note is that some of the saturated fat in coconut oil is lauric acid, a medium fatty acid that may have a more neutral role on heart health and blood cholesterol levels.  Lauric acid can raise both the good (HDL) and bad (LDL) cholesterol levels while other saturated fats can raise LDL levels with no effect on HDL levels. 

Also note that hydrogenated coconut oils would not be recommended since they contain trans fats. If you are consuming a coconut oil choose virgin coconut oil and eat this in moderation.

The health benefits of olive oil and other liquid plant oils trumps coconut oil. 

7.  What about dietary cholesterol?

Be aware that dietary cholesterol is different than the cholesterol found in your blood. Although foods such as eggs or shrimp are high in dietary cholesterol, they are low in saturated fat and therefore have limited influence on cholesterol levels in your blood. This is good news if you enjoy eggs for breakfast or grilled shrimp on the barbeque.

Click here for a printer-friendly PDF