Q: One day fat is bad; the next it’s good. What is the real deal on dietary fat?
—J. Meyers, Philadelphia
A: Once upon a time there was no confusion about healthy eating. We all knew the rules, even if we didn’t always follow them. High complex carbs, heavy on the grains, moderate fish and chicken. Low calorie—even lower fat.
But that was then. Emerging science suggests that we were not only wrong about fat, we were spectacularly, embarrassingly wrong.
It’s clear that our knowledge of what fat is, what it does, and what it does not do needs a serious update. Let’s start by looking at three of the biggest myths related to fat and disease.
Myth 1: Saturated fat causes heart disease .
Actually, it doesn’t. There have been several major, peer-reviewed meta-analyses in the past decade completely debunking the notion that saturated fat is a causal factor in heart disease. In 2010, researchers reviewed 21 studies looking for the relationship of dietary saturated fat to the risk of coronary heart disease. They couldn’t find one. “There is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD (coronary heart disease) or CVD (cardiovascular disease),” they concluded.
This lack of association was confirmed in several other studies, notably a 2014 review in the Annals of Internal Medicine, which found no link between saturated fat consumption and the risk of heart disease or death.
Myth 2: Vegetable oils are good.
Well, not always. Vegetable oils don’t actually come from vegetables. They’re processed from grains such as corn, or from plants such as soybeans. Those we commonly use—corn oil, safflower oil, sunflower oil, canola oil—are frequently from GMO crops, unless they are organic. They’re processed at high heat, often with very harsh chemicals, so by the time they end up on the shelf, there is little if any nutritional value in them. What’s more, they are mostly made up of omega-6 fats, which—in the absence of sufficient omega-3—are pro-inflammatory.
Myth 3: Animal products are unhealthy and don’t belong in a “clean” diet.
It is true that toxic animal products are unhealthy and don’t belong in your diet. But note the word “toxic.” Toxic animal products come from animals that have been raised in unspeakable conditions, fed an inflammatory diet, given massive amounts of antibiotics, injected with hormones and steroids, and fed grain sprayed with potentially carcinogenic chemicals. Most of this meat comes from “factory farms” or CAFOs (confined animal feedlot operations).
Beef that is 100 percent grass-fed and organic is the opposite of toxic meat—in fact, it’s a health food. Absent confinement, the cows graze on their natural diet of pasture. Their omega-3 content is higher, their (pro-inflammatory) omega-6 content lower. They tend to have high concentrations of CLA (conjugated linolenic acid), which has anticancer and anti-obesity properties.
A New Way of Looking at Fat
So the old way of classifying fat—animal fat “bad,” vegetable fat “good”—turns out to be pretty useless. In our 2016 book, Smart Fat, Steven Masley, MD, and I suggest dividing fat into two categories—toxic and nontoxic. The simple take-home? Avoid toxic fat, and don’t worry about the rest.
Man-made trans fats are the poster child for toxic fat, but so are “vegetable” oils that have been used and reused in a restaurant, or low-smoke point oils that have been overheated. And so is any kind of fat that comes from animals who have been fed steroids, hormones, and antibiotics. Avoid toxic fats, regardless of their origin, and embrace clean fats.
Speaking of “good for us,” here are some of the valuable benefits of fat you need to know about.
People are often surprised that dietary fat helps them lose body fat. That’s because we’ve been taught that weight loss is all about calories, and, it’s true, fat has more calories (9 per gram) than carbs or protein (4 calories per gram). But it’s hormones—not calories—that drive weight gain and weight loss. Insulin causes our body to store fat, and it’s pumped up by sugar and carbohydrates. Protein raises insulin levels a little, but not nearly as much as carbs do.
You know what doesn’t move the needle on insulin at all? Fat.
Ghee contains CLA, a polyunsaturated fat that studies show may induce fat loss.
Leptin is the hormone that tells your brain to stop eating when you’re full. In overweight people, this signaling mechanism doesn’t always work well. Your brain becomes “leptin resistant”— leptin is screaming, “Stop eating!” but the brain just doesn’t hear the message.
Leptin resistance is triggered by too many refined carbs. Meanwhile, those same carbs—through the influence of insulin—cause you to store more fat. It’s a double whammy. Less sugar and less refined carbs—together with more fat, fiber, and protein—is the perfect prescription for getting your leptin system working again.
It’s also the perfect prescription for managing another hormone, cortisol. Cortisol— known as the “fight or flight” hormone—causes your blood sugar to rise, which triggers a release of fat-storing insulin. Cortisol also causes the body to store fat around the middle. The solution? More fat, fiber, and protein, less carbs and sugar!
Fat as Anti-Inflammatory
Inflammation has been identified as one of the major promoters of just about every degenerative disease from heart disease to Alzheimer’s. That’s why nutrition experts recommend an anti-inflammatory diet. And two of the most anti-inflammatory substances are both fats—olive oil, and omega-3s (from fish and flax).
Brain Health and Saturated Fat
There’s recently been a flood of interest in ketogenic diets, which are basically high-fat diets that can be very good for the brain. One Mayo Clinic study followed 937 cognitively normal adults for about four years, keeping track of what they ate. Those who ate the most carbohydrates had an 89 percent increase in risk for cognitive impairment, while those who ate the most saturated fat had a 36 percent reduction in risk. “We should increase our consumption of fat while we decrease our consumption of carbohydrates,” says integrative neurologist David Perlmutter, MD.
Eat Fat to Burn Fat
Years ago, long-distance runner and exercise physiologist Stu Mittleman told me, “You gotta eat fat to burn fat.” He was right. Fat is a great source of energy, it cushions and protects the organs, it delivers fatty acids to the brain, and it does not stimulate fat-storing hormones.
The trick is to use fat wisely. Choose nontoxic fats. Swap out those high-omega-6 oils for some omega-9s (macadamia nut oil) or healthy saturated fats. Cook at temperatures below smoke point. (Ghee and avocado oil stand up to 500 degrees.)
Did you know...
Macadamia nut oil is rich in omega-3 fatty acids, and it’s packed with immune-boosting antioxidants.
Add that healthy fat to a diet that’s high in fiber, moderate in clean protein—notice I didn’t say lean—and throw in some nuts, berries, red wine, and chocolate for good measure.
Welcome fat back into your diet. It really shouldn’t have left.
Fat: The Good, The Bad, and The Ugly
- Olives, olive oil, avocados (and avocado oil), nuts and their oils (almonds, pecans, walnuts, pistachios, hazelnuts, macadamia nuts) and seeds and their oils (chia, flax, pumpkin)
- Grass-fed butter
- Fatty fish (preferably wild-caught)
- Fish oil (omega-3)
- Dark chocolate
- Coconut, coconut oil, medium-chain triglyceride (MCT) oil
- Malaysian palm oil
- Eggs (protein and fat)
- Trans fat found in fast foods and packaged foods (also called hydrogenated or partially hydrogenated oils). Trans fats lengthen the shelf life of food. Unfortunately, they do the opposite to you. “Trans fats are biochemically similar to liquid plastic”, says Steven Masley, MD. I call them metabolic poison.
- “Vegetable” oils that have been highly refined and chemically altered through industrial processes; they’re damaged goods, processed with high heat and extracted with nasty chemicals.
- Fats from animals shot full of chemicals, antibiotics, and hormones.