Authors: Chris Kresser
Tags: #Health & Fitness / Diet & Nutrition / Diets, #Health & Fitness / Diet & Nutrition / Weight Loss
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Avoid gluten completely during the Step 1 Reset and for at least two months afterward (for a total of ninety days). Then reintroduce and see how your body reacts.
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If you feel better without gluten and worse when you reintroduce it, you are gluten-intolerant and should strictly avoid it. If you don’t react adversely, I still recommend avoiding or minimizing gluten, but you may choose to have it occasionally as part of your 80/20 rule (a slice of birthday cake, Mom’s lasagna, or a piece of bread when you’re dining out).
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Avoid industrial seed oils and refined sugar. They are high in calories, low in nutrients, and may contribute to inflammation and other health problems. As with gluten (assuming you’re not gluten-intolerant), you may choose to have small amounts of them infrequently as part of your 80/20 rule.
Notes for this chapter may be found at ChrisKresser.com/ppcnotes/#ch4.
Fats are a primary energy source for the body. They also play a role in maintaining healthy skin and hair, regulating body temperature, supporting immune function, insulating internal organs, and aiding in the absorption of the fat-soluble vitamins (A, D, E, and K).
But fats, in general, get a bad rap in our heart-healthy and fat-obsessed diet culture, partly because we’re trained to put fat in the foods-to-avoid category. A food that is described as high-fat sets off alarm bells for most of us. But, as you’re about to see, not all fats affect the body in the same way, and while some are harmful, many have beneficial, life-extending properties. When you follow your Personal Paleo Code, you’ll find that it’s easy to select the right variety and combination of fats.
Gasoline and diesel are both fuel that cars can run on. If you put gasoline in a diesel engine, or vice versa, the engine may run but it won’t run well—or for very long. In a similar way, the human body can run on the entire range of fats (combined with carbohydrates and proteins). But it runs much better on the types it was designed to run on, and if you eat too much of the other kinds, the body will eventually break down.
Let’s begin by examining the different types of fat to determine which are the preferred fuels for the human body.
The main fats we encounter in foods are:
•
Saturated fats (long-and medium-chain)
•
Monounsaturated fats
•
Trans fats (natural and artificial)
•
Polyunsaturated fats
During the Step 1 Reset, it’s best not to worry too much about macronutrient ratios. That said, as a starting place, choose a rough target for carbohydrate intake based on your individual circumstances (see
chapter 18
for more on this) and eat that amount. Your remaining calories will come from protein and fat, and since most people naturally eat the amount of protein their bodies need, you also won’t have to think about how much fat to eat; that will fall into place without any calculations on your part. For example, say you decide to shoot for 30 percent of calories from carbohydrates. In the United States, most people get about 15 percent of their calories from protein. That means your fat intake would be about 55 percent of calories. This may be much more fat than you’re accustomed to eating, especially if you’ve been following a low-fat, high-carbohydrate diet. But remember that the
quality
of fat you eat is often more important than the
quantity
when it comes to health and even weight regulation.
With this in mind, let’s take a closer look at the various types of fat and their effects in the body.
All fats are made up of molecular chains of carbon, hydrogen, and oxygen atoms. They are classified as short, medium, or long, based on the length of the molecular chain.
Long-chain saturated fats
(such as myristic, palmitic, and stearic acid) are found mostly in the milk and meat of ruminant animals like cattle
and sheep. They form the core structural fats in the human body, making up 75 to 80 percent of fatty acids in most cells, and they’re the primary storage form of energy. In other words, when the body stores excess energy from food for later use, it stores it primarily as long-chain saturated fat. Unlike polyunsaturated fats and carbohydrates, like glucose and fructose, saturated fats have no known toxicity—even at very high doses—if insulin levels are in a normal range. Long-chain saturated fats are more easily burned as energy than polyunsaturated fats, and the process of converting saturated fat into energy leaves no toxic by-products. In fact, it leaves nothing but carbon dioxide and water.
Saturated fats have many other benefits. They:
•
Play an important role in bone health by helping to incorporate calcium into the skeletal system
•
Protect the liver from damage by alcohol, medications such as acetaminophen, and toxins
•
Have beneficial effects on cardiovascular function, including reducing levels of lipoprotein(a)—also known as Lp(a)—an inflammatory substance in the blood that promotes heart disease, which subsequently reduces mortality caused by stroke. They also improve lipid profiles by increasing HDL (which you probably know as the good cholesterol, as opposed to the bad cholesterol, LDL), decreasing triglycerides, and making LDL particles larger and more buoyant, which means they are less likely to cause harm.
•
Support healthy immune function
•
Deliver the fat-soluble vitamins A, D, K, and E to the cells and tissues of the body
•
Regulate the availability of beneficial polyunsaturated fatty acids like DHA
Fattier cuts of beef, lamb, and pork; cream, whole milk, butter, ghee. They are found in smaller amounts in coconut products and egg yolks.
Food
: Coconut oil
Saturated Fat, %
: 87
Food
: Dairy products
Saturated Fat, %
: 64
Food
: Tallow (beef)
Saturated Fat, %
: 50
Food
: Palm oil
Saturated Fat, %
: 49
Food
: Beef, chuck roast
Saturated Fat, %
: 40
Food
: Lard
*
Saturated Fat, %
: 39
Food
: Beef, brisket
Saturated Fat, %
: 39
Food
: Beef, ground (20% fat)
Saturated Fat, %
: 38
Food
: Duck fat
Saturated Fat, %
: 33
Food
: Chicken fat
Saturated Fat, %
: 30
Food
: Egg yolks
Saturated Fat, %
: 30
Along with monounsaturated fats (which we’ll discuss shortly), saturated fats should make up the bulk of your fat intake.
If you’re worried about saturated fat causing heart disease, it’s true there are certain situations where saturated-fat intake should be moderated, and I’ll explain those in later chapters. However, for most healthy people, the evidence that saturated fat leads to heart disease is weak at best. For decades we’ve been told that eating saturated fat increases cholesterol levels in the blood and that high cholesterol levels clog arteries and cause heart disease. But does the research actually support that theory?
Some studies do show that increased saturated-fat intake raises blood cholesterol levels. But these studies are almost all short-term, lasting only a few weeks. Longer-term studies have not shown an association between saturated-fat intake and blood cholesterol levels. In fact, of all of the long-term studies examining this issue, only one of them showed a clear association between saturated-fat intake and cholesterol levels, and even that association was weak. Perhaps saturated fat contributes to heart disease by some mechanism other than raising cholesterol? Not according to the research. A large review of twenty-one studies covering almost 350,000 participants found no association between saturated-fat intake and cardiovascular disease. Moreover, studies on low-carbohydrate diets (which tend to be high in saturated fat) suggest that they not only don’t raise blood cholesterol but have several beneficial impacts on cardiovascular-disease risk markers. (For detailed information on these studies and other findings, please see the notes for this chapter on my website.)
Medium-chain saturated fats
(and medium-chain triglycerides) are found in coconut milk and breast milk, and they have unusual properties. They’re metabolized differently than long-chain saturated fats: they don’t require bile acids for digestion and they pass directly to the liver via the portal vein. This makes medium-chain saturated fats a great source of easily digestible energy. They’re so easy to digest, in fact, that they’re used in the liquid hospital formulas fed to patients who have had sections of their intestine removed and aren’t able to digest solid food.
In addition to being a good energy source, medium-chain saturated fats have therapeutic properties:
•
They’re high in lauric acid, a fat found in mother’s milk that has antibacterial, antiviral, and antioxidant properties.
•
They promote weight loss. They have a lower calorie content than other fats; they are not stored in fat deposits as much as other fats; and they enhance fat burning (by thermogenesis).
•
They promote the development of ketones, one of two substances (along with glucose) the brain can use as fuel. Ketones and ketone-generating diets have been shown to benefit several neurological conditions, including seizure disorders, Parkinson’s, and Alzheimer’s.
Coconut: its flesh, oil, milk, and butter
Coconut oil is an especially good cooking fat, because it’s not as vulnerable to the oxidative damage that occurs with high-heat cooking using other fats.
Kara was thirty-six years old and had been trying to get pregnant for two years when she came to see me. When I reviewed her diet I noticed that she was drinking skim milk and severely limiting other traditional saturated fats like butter, ghee, lard, and coconut oil.
This isn’t unusual, of course; people have been told for decades that saturated fat will clog arteries and cause heart disease. Yet many traditional cultures emphasize the importance of these fats in promoting optimal health, and this is especially true during the preconception period. For example, the Masai tribe in Africa allowed women to become pregnant only after they’d spent several months drinking full-fat cow’s milk in the wet season, when the grass is lush and the nutrient content of the milk is especially high.
Modern research has confirmed that saturated fats may promote fertility. A study at the Harvard School of Public Health found that women who ate two or more servings of low-fat dairy foods per day, particularly skim milk and yogurt, increased their risk of infertility by more than 85 percent compared with women who ate less than one serving of low-fat dairy food per week. I instructed Kara to reincorporate traditional saturated fats into her diet and switch from nonfat to full-fat dairy products. After just three months on this new dietary
regime, Kara e-mailed me with the news: she was pregnant! Kara continued eating this way throughout her pregnancy (gaining a normal amount of pregnancy-related weight) and delivered a healthy eight-pound, two-ounce baby girl.
Monounsaturated fats, such as oleic acid, are found primarily in olives, avocados, some meats, and certain nuts, like macadamias. Like saturated fats, monounsaturated fats form the core structural fats of the body and are nontoxic even at high doses. Interestingly, monounsaturated fats seem to be the only fats that typically fat-phobic groups, like the American Heart Association, and fat-friendly groups, like the Atkins diet organization and other low-carbers, can agree are completely healthy.
Monounsaturated fats are also known for their beneficial effects on cardiovascular-disease risk markers. They reduce LDL and triglycerides and increase HDL, decrease oxidized LDL, reduce oxidation and inflammation, lower blood pressure, decrease thrombosis (the formation of blood clots), and may reduce the incidence of heart disease. Some studies also suggest that monounsaturated fats promote healthy immune function.
Olives, olive oil, avocados, lard (pork fat), duck, chicken, egg yolk, macadamia nuts, almonds.
Food
: Macadamia nuts
Monounsaturated Fat, %
: 77
Food
: Olives and olive oil
Monounsaturated Fat, %
: 74
Food
: Avocado
Monounsaturated Fat, %
: 64
Food
: Almonds
Monounsaturated Fat, %
: 62
Food
: Duck fat
Monounsaturated Fat, %
: 49
Food
: Egg yolks
Monounsaturated Fat, %
: 46
Food
: Lard
Monounsaturated Fat, %
: 45
Food
: Chicken fat
Monounsaturated Fat, %
: 45
Food
: Tallow (beef)
Monounsaturated Fat, %
: 42
Food
: Butter
Monounsaturated Fat, %
: 26
But be aware that certain foods that are high in monounsaturated fats, like nuts and avocados, can contain significant amounts of linoleic acid, an omega-6 polyunsaturated fat. As I’ll explain below, linoleic acid is pro-inflammatory if consumed in high amounts when intake of EPA and DHA are low.
There are two types of trans fats:
natural
and
artificial.
Naturally occurring trans fats are formed when bacteria in the stomachs of grazing animals, such as cows or sheep, digest the grass the animal has eaten. Conjugated linoleic acid, or CLA, is a natural trans fat found in moderate amounts (between 2 and 9 percent of total fat) in grass-fed-animal meat and dairy products, and to a lesser degree in grain-fed-animal products. It is also produced in our bodies from the conversion of other naturally occurring trans fats in those same animal products.