by Mark Hyman
In Dr. David Perlmutter’s groundbreaking book Grain Brain, he also documents the role of fat in the brain. There is an abundance of research showing that carbs cause brain aging and fat prevents it. In fact, some now call Alzheimer’s type 3 diabetes because insulin resistance causes brain damage. A study from the Mayo Clinic found that people who eat a ton of carbs quadruple their risk of getting pre-dementia, known as mild cognitive impairment. The same study showed that people who ate the healthiest fats had a 44 percent lower risk of early dementia, and those who ate more good-quality protein from chicken, meat, and fish had a 21 percent lower risk of early dementia.5
Another study of more than 8,000 people over the age of sixty-five found that 280 of them got dementia over the span of four years. The researchers looked at the participants’ diets and found that those who ate the least brain-healthy omega-3 fats had a 37 percent increased risk of dementia.6 Those who ate the most fish had a 44 percent reduction in the risk of getting dementia. Those who ate the most olive oil, walnuts, and flaxseeds had a 60 percent reduction in the risk of getting dementia. But they also found that those who ate the most omega-6 oils had twice the risk of dementia.
EATING FAT HELPS WITH SEIZURES, DEPRESSION, ADD, AUTISM, TRAUMA, AND MORE
Your brain is 60 percent fat, and much of it is made of omega-3 fats and cholesterol. When you eat a low-fat diet, you are starving your brain.
Fat is critical for your brain. Lack of fat in the diet has been linked to neurodegenerative diseases; mental disorders such as depression,7 suicide, and aggressive behavior;8 ADD9 and autism;10 stroke; and trauma.11 On the other hand, supplementing the diet with omega-3 and other good fats has been linked to improvement in all these conditions. Omega-3 fatty acids stimulate beneficial gene expression and boost the activity of your brain cells, increase connections between brain cells, and even help the formation of new brain cells (neurogenesis). They help reduce brain inflammation and improve cognitive function. They can aid depression and even recovery from brain injury.12 Very high-fat ketogenic diets are used to control epilepsy13 and are now being used for ALS (amyotrophic lateral sclerosis)14 and other neurologic disorders, including brain cancer.15
Bottom line: Fat is good for your brain!
EATING FAT REDUCES INFLAMMATION AND AUTOIMMUNE DISEASE
Bad fats such as the omega-6 refined vegetable oils cause inflammation, but good fats reduce inflammation. Omega-3 fats have been extensively studied as a way of treating inflammatory and autoimmune disease. They modulate inflammatory pathways and help improve expression of anti-inflammatory genes.
There have been many studies assessing the benefits of supplementation with fish oil in inflammatory and autoimmune diseases in humans, including rheumatoid arthritis, Crohn’s disease, ulcerative colitis, psoriasis, lupus erythematosus, multiple sclerosis, and migraine headaches. These studies show great benefits, including decreased disease activity and less of a need for anti-inflammatory drugs.16 I have found that fish oil supplementation along with a low-glycemic, anti-inflammatory, higher-fat diet that is also gluten- and dairy-free can dramatically help my patients with autoimmune disease.
Gamma linolenic acid (GLA) has been well researched in autoimmune disease and shown to be effective.17 It is found in evening primrose oil or borage oil and can be synthesized by the body, but often not very well, especially under conditions of illness. I have used it effectively in combination with diet and other therapies in many of my autoimmune patients.
EATING FAT BOOSTS YOUR SPORTS PERFORMANCE
We have all been trained to believe that if you want to enhance your sports performance, you need to carb-load. Eat that big bowl of pasta before a race to make sure you top up your muscle carbohydrate stores (glycogen) so you don’t hit the wall… that sort of thing. You can store up to 2,000 calories of carbs as glycogen in your muscles, but the average lean athlete has about 40,000 calories of energy stored as fat. Wouldn’t it be great if you could switch from carb burning to fat burning?
Many scientists have studied high-fat, low-carb diets for athletes. Two in particular have led the way: Dr. Jeff Volek and Dr. Stephen Phinney. They have authored hundreds of papers untangling the biology of high-fat, low-carb diets on every aspect of physiology—even in extreme athletes who are insulin sensitive and not carbohydrate intolerant. In their books The Art and Science of Low Carbohydrate Living and The Art and Science of Low Carbohydrate Performance, they go into great detail on how your body can switch from burning mostly carbs to burning mostly fat. This is called keto-adaptation. The key is to keep insulin levels very low. Higher levels of insulin inhibit or block fat burning, making it impossible to mobilize fat stored in your tissues. Drs. Volek and Phinney explain the benefits of switching from carb burning to fat burning for exercise:
Low-carb (high-fat) diets are anti-inflammatory and so reduce oxidative stress during exercise, reduce lactic acid buildup, and help the body recover faster between exercise sessions.
Once you adapt to a low-carb diet (which takes about two weeks), your body relies primarily on burning body fat during and between exercise sessions, so you don’t have to load up on carbs to restore glycogen levels. You can eat a lot of fat without risk.
Endurance and power- or strength-training athletes can use carb-restricted high-fat diets and even get better body composition and strength.
I know eating a low-carb, high-fat diet has made me stronger, fitter, and faster even as I’ve aged. And when I load up on coconut oil, which contains medium-chain triglycerides,18 which boost performance, increase fat burning, and help build muscle, before a long bike ride, I can go and go without pooping out.
EATING FAT GIVES YOU BEAUTIFUL SKIN, HAIR, AND NAILS
Ever wonder how trainers get horses to have beautiful, shiny coats? They give them flaxseeds, which are a rich source of omega-3 fats. Lack of omega-3 fat in your diet from fish or plant sources can cause significant health problems. Most people slather creams, lotions, and potions on dry skin, put on all sorts of hair products to bring their hair back to life, and use nail products to strengthen their nails, but most of our outside problems come from inside. Omega-3 deficiency can cause dry, itchy, flaky, even discolored skin. It can also cause rough, bumpy chicken skin on the backs of your arms. I know you are checking that now! Your fingertips may crack and peel. Your hair may be dry, stiff, and tangled; you may have dandruff and hair loss. Your fingernails might grow slowly or become brittle and chipped. Omega-3 fats can relieve all of these problems. For some people with really problematic skin, applying a combination of flax and borage oil can have amazing results.
EATING FAT ENHANCES YOUR SEX LIFE
You might be surprised to learn that your sex hormones are produced from cholesterol in the body. We eat an average of 146 pounds of flour and 152 pounds of sugar per person per year in America, which spikes insulin, driving the storage of belly fat, increasing estrogen in men (belly fat cells produce more estrogen) and sending their testosterone levels plummeting. This leads to low sex drive, sexual dysfunction, muscle loss, loss of body hair, and man boobs! For most men, cutting out the carbs and boosting fats fixes the problem without having to resort to testosterone replacement.
Low-fat diets can cause women to stop menstruating or to experience irregular, heavy periods and infertility. They can increase belly fat, raise testosterone levels, and trigger acne, facial hair, and hair loss on the head, whereas high-fat, low-carb diets can reverse all that.
FAT AND CANCER: SHOULD WE BE WORRIED?
Let’s take a look at whether we should be worried about fat and cancer. This probably won’t surprise you by this point, but there is conflicting evidence. Some studies show that fat and cancer are not connected, others show they might be, yet others show fat might be protective, and even others are using very high-fat ketogenic diets to starve cancer cells because they can run only on sugar, not on fat. So how do we make sense of this?
Truthfully it is hard. The problem, as I have described, is the poo
r state of nutrition research. In large population studies where diets are assessed by food frequency questionnaires (which are not super accurate because who really remembers what they ate from week to week?) and where many other factors can explain associations, it is hard to draw clear conclusions. It is why population studies can’t prove cause and effect. For example, in some studies it was found that people who had more saturated fat might be at higher risk for more cancer. But was it the saturated fat or the overall dietary and lifestyle pattern of the saturated-fat eaters (less exercise, more smoking, more refined and processed foods, more fried foods, fewer fruits and vegetables, heavier weight of the saturated-fat eaters)? It may not be the saturated fat at all. Many large population studies found, for example, that increased fat intake was linked to breast cancer, but then when large randomized controlled experiments were done to assess true cause and effect, no link between dietary fat and breast cancer could be found.19
Population studies also show contradictory results. Some show that more fat or certain fats cause cancer, while other studies show exactly the opposite.20 Large reviews have trouble finding consistent links between fat and cancer.21 That is why I rely more on basic science and experiments combined with an understanding of basic biology and, in this case, cancer biology. The data is still coming in and we don’t have all the answers, which is why I advocate a sensible approach based on whole foods and good fats.
Here’s what we do know about cancer. It is a complex disease that results from environmental insults (like toxins, smoking, etc.), diet, and stress. We also know certain things for sure. Insulin resistance or pre-diabetes or type 2 diabetes dramatically increases the risk of most common cancers (prostate, breast, colon, pancreas, liver, etc.). We also know that inflammation increases cancer risk. Everyone agrees that vegetables and fruits contain powerful anticancer compounds. One study in China measured metabolites of broccoli and cruciferous vegetables in the urine and found that those with the highest amounts of these compounds had the lowest risk of cancer.22 Other studies link certain foods strongly with certain cancers, for example, dairy with prostate cancer.23
Some fats, however—the essential omega-3 fatty acids such as EPA and DHA—do seem helpful and are good for almost every other health problem because they are critical components of our biology. Many studies show that omega-3 fats have anticancer properties.24 They reduce inflammation, improve insulin resistance, and work through other cellular mechanisms to inhibit cancer pathways in colon cancer,25 breast cancer,26 and prostate cancer.27 Many studies show that in the face of a diet high in omega-6 PUFAs from vegetable oils, omega-3 fats don’t work that well. Other studies have shown that saturated fats are harmful only in the face of a high-carb diet or a diet low in omega-3 fats. In fact, much research is being done now on using ketogenic or very high-fat diets (60 to 70 percent fat) for treating cancer,28 including brain cancer and colon cancer.29 It seems that high-fat ketogenic diets are toxic to cancer cells, while helping the patient thrive.
I don’t believe there is one diet that is good for your heart, and another that prevents cancer, another that prevents dementia, and even another that prevents diabetes. I believe we were much more intelligently designed than that, that nature and our biology are more elegantly constructed. There must be one set of principles that makes sense for humans. Unfortunately, because of the sad state of nutrition science, we have to piece together the story.
Part of the problem with nutrition science is it tries to draw conclusions by teasing apart individual nutrients and separating them from the overall dietary pattern. But this just doesn’t make sense. We evolved eating whole real food, not individual ingredients or types of fat that we dialed up or down based on the latest research. While there might be risks, I think that a whole-foods, evolutionary approach to eating, informed by science and our current understanding of molecular biology and physiology, makes the most sense. This perspective is the foundation of the Eat Fat, Get Thin Plan outlined in Part III.
So there you have it: all the research, facts, and figures on fat. I hope by now you’re as convinced as I am that the low-fat era must finally be put to an end, and that eating healthy fat is the key to losing weight, preventing disease, restoring vitality, and—most of all—enjoying many of the foods you love!
PART III
THE EAT FAT, GET THIN PLAN
And Pharaoh said unto Joseph, Say unto thy brethren, This do ye: lade your beasts, and go, get you unto the land of Canaan; And take your father and your households, and come unto me: and I will give you the good of the land of Egypt, and ye shall eat the fat of the land.
—Genesis 45:17–18
10
What Should I Eat?
Now that you know the whole story about how we got into this big, fat mess, and why you need to change how you think about food and fat, let’s get to what you really want to know:
How can I lose weight and improve my health?
What foods should I avoid?
How do I increase the fat in my diet—and which ones should I choose?
What carbs should I eat?
How much protein do I really need?
How can I combat cravings?
The Eat Fat, Get Thin Plan will answer these questions and more. I’m going to share with you the program I designed that will revolutionize everything from your mind-set to your pantry, and from your waistline to your overall health. In just twenty-one days, you’ll know not only what to eat but how to fuel your body on every level so you can look and feel fantastic.
The Eat Fat, Get Thin Plan will jump-start you on the path to losing weight, rebooting your metabolism, and getting healthy. After the twenty-one days, as you’ll read about in Chapter 14, you’ll have the option to stay on the Eat Fat, Get Thin Plan to continue your weight loss and healing, or transition to what I call the Pegan Diet (my vetted combination of Paleo and vegan), which includes whole grains, beans, and—in the secondary stage—the reintroduction of some gluten, dairy, and the occasional treat. I focus specifically on the cross-section of vegan and Paleo because the middle ground between these two approaches is the most doable, sensible, sustainable, delicious, healthful, and science-based way of eating. It incorporates elements from other diets that have been found to be healthful, such as the Mediterranean diet. This long-term approach to eating is the result of decades of research and personal experience working one on one with thousands of patients.
COMPARING VEGAN AND PALEO DIETS
You’d think the research would clarify the answer to the question of what we should eat, but it just makes for more confusion. Vegan diet studies show they help with weight loss, reverse diabetes, and lower cholesterol. Paleo diets seem to do the same thing. So should you be shunning animal foods and eating only beans, grains, and veggies, or should you eat meat and fat without guilt and give up all grains and beans? There are great aspects to both perspectives, but they are incomplete by themselves. Essentially, the members of each camp adhere to their diet with near religious fervor, pointing only to studies that validate their point of view. We call this cherry picking.
Typically these studies compare high-quality versions of Paleo or vegan diets with the standard American diet, which is high in processed foods, sugar, refined carbs, poor-quality industrial animal products, and refined oils. A study of any diet of whole foods—vegan or Paleo—will do far better than the awful processed industrial diet. But what happens when you compare two whole-food, good-quality vegan diets—one low-fat and one high-fat? This has been done, and the high-fat, high-protein, low-carb, low-glycemic vegan diet (Eco-Atkins) performed better for weight loss and lowering cholesterol than the low-fat vegan diet that avoided nuts, seeds, and avocados.1
Comparing a vegan diet of chips, Coke, bagels, and pasta to a Paleo diet of healthy veggies and grass-fed meat wouldn’t be very helpful either; nor would comparing a Paleo diet of feedlot meat, bologna, and few fresh veggies to a whole-foods, low-glycemic vegan diet. But no one has yet done the
study that compares the ideal healthy Paleo diet with the ideal healthy high-fat vegan one. My guess is that both can be healthful and that some people might do better on the higher-fat animal-food diets and others better on the plant-based higher-fat diets. LeBron James, considered one of the greatest basketball players of our time, follows a Paleo diet. The number one tennis player in the world, Novak Djokovic, cut out gluten and dairy and ate a higher-fat diet and went from losing match after match to winning every major tennis tournament in a year. Rich Roll completed five Ironman triathlons in seven days on a high-fat vegan diet. Humans are amazingly adaptable. But the only important question is, What is the right diet for the human that matters most—you?!
You should base your food and lifestyle choices on how your body responds. Listen to your body. It will tell you what it likes. It takes observation and time to figure it out. But your body is the smartest doctor in the room.
BEST OF VEGAN + BEST OF PALEO = PEGAN
The Pegan Diet combines the best of the Paleo and vegan diets.