Now that fat is overcoming its bad reputation, it's becoming trendy to add it to food and drinks for health reasons -- whether that's putting butter in your coffee for dubious benefits, or swapping "Lite" salad dressing for a drizzle of bacon grease. But when does adding fat make sense, and when is it a bad idea?
Photo by Taryn.
Fats Have Different Properties, But None Are Magical
There are devotees of coconut oil, olive oil, you name it -- somebody is exhorting you to work more of it into every meal you can. But are any of these oils really special?
Different oils typically become trendy on the basis of their fatty acid content: if you heard it's good to put flax oil on your food, that's because it's rich in a type of omega-3's.
Any oil or any fatty food is going to include a mix of fatty acid types. This chart gives the breakdowns for several. For example, lard contains a lot of saturated fatty acids but also a lot of monounsaturated fatty acids. Here are the types:
- Saturated fatty acids were once demonized, but are now earning back some respect. These are a major component of animal fats and are found in butter, cream, lard, and bacon.
- Medium-chain fatty acids, found in coconut oil and in "MCT oil" supplements, are metabolized a little differently than the other fatty acids and may have some mild fat-burning properties if you use them in place of other fats, although there are some caveats to that.
- Monounsaturated (omega-9) fatty acids are considered heart-healthy "good" fats. Their best-known sources include olive oil and avocados.
- Polyunsaturated fatty acids include the omega-3's found in fish and fish oils and, in a less potent form, in some nuts and seeds, and omega-6's, found in seed-based oils like corn and canola. Both are required in our diet for different reasons: omega-3's are made into anti-inflammatory hormones, and omega-6's are made into pro-inflammatory ones. Some nutritionists lump both together as "good" fats, while others emphasise that the ratio between the two is important: most of us should get more omega-3 and less omega-6.
- Trans fatty acids, at least the artificial version found in cheap pastries and canned frostings, are pretty much universally agreed to be bad for you.
Here's the problem with adding fats to food: the "good" and "bad" designations tend to come from research that substitutes the fats for each other, rather than eating the same meal with or without fat. So you have to make sure that your meal could really use the extra fat; and then, if that's the case, choose the fat that best meets your goals.
So if you're pretty sure you need more omega-3's in your diet, and if you're sitting down to a meal that is low in fat to begin with -- say a salad, or some pasta with veggies and a low-fat sauce -- a drizzle of flaxseed oil would be a fine addition to that dish.
On the other hand, if the meal already has a reasonable amount of fat in it, adding more is just going to add calories without necessarily conveying any benefits. In that case, consider swapping out one type of fat for another that fits your goals better -- like maybe using coconut rather than canola oil as you fry up the veggies.
Fat Helps Vitamin Absorption
It's true that adding fat to a meal can help us absorb some of the vitamins in it. Vitamins are small organic molecules that we need in our diet, but can't make in our bodies. If you eat a varied, healthy diet in reasonable amounts, you probably get plenty of all the vitamins your body needs. If you were to eat super low fat meals, though, that would interfere with your digestive system's ability to get those vitamins out of your food and into your bloodstream.
If you're the type of person who eats lots of salads and veggie dishes (low fat or otherwise) and are concerned about your vitamin intake, you are probably a healthy eater who is not at risk for a vitamin deficiency. Just saying. But biochemically speaking, does adding fat to food help vitamin absorption? Heck yeah.
Vitamins A, D, E, and K are all fat-soluble, so you need at least a little fat in a meal to help absorb them. (This isn't the case for Vitamin C or any of the B vitamins, which are water soluble.) Tests on salads with fat-free, low-fat, and high-fat dressings have shown that you absorb more carotenoids (like Vitamin A) from a salad with a high-fat dressing. The same is true of salads that contain eggs, since the yolk contains fat.
It's reasonable to assume these principles apply to other vitamin/fat combos, like eating broccoli with butter or cheese -- or even alongside a cheeseburger.
Fat In Beverages Is Mostly Useless
Dave Asprey, the genius who brought us butter coffee and all its dubious claims is now selling an even easier-to-ridicule product: FatWater, a suspension of fat droplets in water.
The health claims tacked onto these products don't make much sense, as food science researchers have noted: While MCT oil may lead to slightly more fat burning when swapped for other oils, adding a tablespoon or two to a beverage isn't likely to have the same effect. Meanwhile, the only thing fat has been shown to help you absorb is fat-soluble compounds like the vitamins we discussed; it doesn't improve hydration like FatWater's maker claims.
Now, if the beverage you're talking about is a smoothie, there's more reason to add fat. A smoothie is essentially food in liquid form. Too often, smoothies just contain carbohydrates, but a healthy, filling smoothie should contain protein and fat too. Almond butter (or other nut butters) contain both, and taste great; full-fat dairy, including milk or yogurt, is another option that provides that one-two punch. These additions make the smoothie more filling, and slow down the sugar's rush into your bloodstream.
Some Meals Need More Fat
Due to decades of bad advice, we got used to thinking of low-fat food as healthy; and it's true that it can be lower in calories. But fat helps us feel more full, and counteracts the "carb coma" that can follow after a meal heavy in sugars and starches. That means that a diet with a healthy amount of fat (generally held as 20-35%, although some would say you can safely go a lot higher) may help you eat less food in the long run.
Extremely low fat meals make us miss out on vitamins and are just plain unbalanced -- so go ahead and add some butter to that toast or olive oil to that pasta. But remember you're just filling out a healthy ratio of macronutrients, not applying a magic elixir.