There are two competing ideas in designing the optimal diet. On one hand, a high fat diet is healthy because it encourages the burning of fat stores and provides a nice stable energy source throughout the day. On the other hand, fats oxidize easily causing oxidative stress. So how much fat should we eat?
The answer is that it’s a little bit complicated. You should eat different types of fats in different amounts, and it matters what you eat the fats with. The essential polyunsaturated fats (PUFAs) are of course essential, and getting enough Omega-3 is important to keep your Omega-3/Omega-6 ratio as close to 1:1 as possible — easiest done by consuming plenty of Omega-3. But the polyunsaturated fats are also the least stable and oxidize very readily. Fish oil, for example, will go rancid and smell like a dead, rotten, stinky fish if left in sunlight or exposed to heat. Clearly you don’t want to eat that. As this fat breaks down in your body, it oxidizes and releases free radicals. You’ve probably heard of these before with all of the press they’ve gotten in the last few years. The media is correct; they are not good for you: free radicals damage your DNA and cause aging; some nutritionists even say that this oxidative stress is the primary driver behind aging.
So while eating lots of fats is important for a healthy diet, it is equally important to counterbalance the oxidative stress that fat puts on your body with antioxidants. This means eating fatty foods with lots of antioxidants, which are found in the skins of fruits, in leafy green vegetables, coffee, chocolate, and tea. These antioxidants will bind to the free radicals and neutralize them before they can cause oxidative damage, sparing your DNA from unnecessary aging.
This oxidative stress is also the reason that fried foods are so notoriously bad for you. Frying is usually done with vegetable, canola, peanut, or soy oil, all of which are full of unstable polyunsaturated Omega-6. What’s worse, frying oxidizes these fats, putting them in a highly reactive state when you consume them. If you are going to cook, be sure to use stable fats like coconut oil or unrefined olive oil (virgin olive oil is less stable). This will minimize the oxidation that happens while cooking.
Let’s say you go out with friends on a Friday night and just can’t pass up those fries at the bar. If you absolutely have to eat fried food, there’s a quick solution: take some Vitamin E (alpha-tocipheral) before you eat. Vitamin E is a powerful antioxidant and taking this during a meal can help neutralize some of the free radicals. In fact, Vitamin E is so effective at preserving unstable fats that it is often fed to poultry to help meat stay fresh longer and it is added to fish oil supplements to increase their shelf life. But keep in mind that this is a band-aid and that pure antioxidants are not necessarily healthy in the long run. Studies have shown that daily Vitamin E consumption (and other antioxidants) can actually increase cancer rates, not decrease them.
As far as keeping that ideal high-fat diet, eat lots of stable fats that don’t oxidize as easily. This means eating saturated fats and monounsaturated fats — they are far less reactive than PUFAs and thus less readily oxidize and cause DNA damage. These are best found in fatty vegetables like avocados, coconuts, macadamia nuts (but not other nuts because most nuts have a lot of Omega-6), and olive oil.
- Eat the unstable polyunsaturated fats in moderation and with leafy greens and fruits
- Focus on getting most of your fat as monounsaturated fat and saturated fat
- Don’t eat fried food or cook with unstable fats — and if you do, eat it with Vitamin E
If you’re a nerd like me, I recommend the book Food Lipids: Chemistry, Nutrition, and Biotechnology, which goes deep into the chemical reactions and processes behind lipid metabolism and degradation.