Your Personal Paleo Code: The 3-Step Plan to Lose Weight, Reverse Disease, and Stay Fit and Healthy for Life (14 page)

I’ve listed the approximate smoke point of various fats and oils below. For high-heat cooking, choose fats with the highest smoke points, such as ghee, extra-light (not extra-virgin) olive oil, palm oil, expeller-pressed (refined) coconut oil, macadamia oil, and beef tallow. Butter, extra-virgin olive oil, and extra-virgin coconut oil have relatively low smoke points and are best for noncooking uses (for example, putting them on previously cooked foods).

Fat
: Ghee

Smoke Point (°F)
: 485

Fat
: Olive oil (extra light)

Smoke Point (°F)
: 468

Fat
: Palm oil

Smoke Point (°F)
: 455

Fat
: Coconut oil (expeller pressed)
^*

Smoke Point (°F)
: 450

Fat
: Macadamia oil

Smoke Point (°F)
: 413

Fat
: Beef tallow

Smoke Point (°F)
: 400

Fat
: Duck fat

Smoke Point (°F)
: 375

Fat
: Lard

Smoke Point (°F)
: 370

Fat
: Coconut oil (extra virgin)

Smoke Point (°F)
: 350

Fat
: Olive oil (extra virgin)

Smoke Point (°F)
: 320

Fat
: Butter

Smoke Point (°F)
: 250–300

Notes for this chapter may be found at ChrisKresser.com/ppcnotes/#ch5.

Carbohydrates are one of the two main energy sources (the other is fat) for humans. They are found in many foods, including refined grains and sugars that have contributed to so much modern disease. But there are many excellent (and often overlooked) dietary sources for healthy carbohydrates that you’ll learn about in this chapter as you continue to construct your Personal Paleo Code.

First, however, let’s look at how carbs work. In the body, all carbohydrates in food are ultimately broken down and converted into simple sugars (glucose and fructose) or indigestible fiber. But while glucose, fructose, and fiber are all technically carbohydrates, they each have different effects on the body. Let’s look at each of them in more detail.

Glucose is a simple sugar (or monosaccharide) found mostly in plant foods like fruits, vegetables, starches, and grains. It can be broken down from sweeteners like table sugar (sucrose) and honey. Glucose has three main uses in the body:

Glucose preceded fatty acids as a fuel source for living organisms by a very long time, and it is the building block of foods that have the longest evolutionary history of use by mammals like us. The fact that glucose can be broken down in the body from protein is often used as an argument that we don’t need to eat glucose. But rather than viewing this as evidence that glucose isn’t important, we might view it as evidence that glucose is so metabolically essential that we evolved a mechanism to produce it even in its absence in the diet.

One of the few differences between the human digestive tract and that of a true carnivore, like a lion, is that humans produce an enzyme called amylase. Amylase allows us to digest starch—a long chain of glucose molecules we can’t absorb—into single molecules of glucose that easily pass through the gut wall into the bloodstream.

While glucose from fruits, vegetables, and starches is generally well tolerated, too much of it—in the form of sucrose-sweetened beverages or concentrated sweeteners, for example—can cause weight gain and metabolic problems.

Fructose is another simple sugar found primarily in fruits and vegetables. While it has the same chemical formula and caloric content as glucose, it has a different structure and is processed differently. Rather than being absorbed by the cells, it is shunted directly to the liver for conversion into glucose or fats. About 50 percent of fructose ends up as glucose, 25 percent becomes lactate (a chemical produced during normal metabolism and exercise), and 15 percent or more becomes glycogen, the principal storage form of glucose. The remainder is burned directly for energy, and a small portion—as little as 2 to 3 percent—is converted to fat.

There’s little question that excess fructose from high-fructose-corn-
syrup-sweetened beverages like sodas contributes to weight gain. One of the main reasons for this is that most people don’t cut calories somewhere else to compensate for the additional calories that come from drinking a couple of sodas each day. They simply end up taking in more calories overall. It’s also true that excess fructose has distinctly harmful metabolic effects when compared to glucose.

However, despite some claims to the contrary, there’s no evidence that we should avoid whole fruit simply because it contains fructose. There’s nothing fattening or toxic about fructose when it’s consumed in moderate amounts from whole fruits and vegetables. And since whole fruit contains fiber and other nutrients, it’s difficult to eat a lot of fruit without also reducing intake of other foods. Fruit has been part of our species’ diet for as long as we’ve been recognizably human. We’ve adapted to eating it, and we’re capable of processing the fructose it contains. Studies overall suggest that eating whole, fresh fruit may actually decrease the risk of obesity and diabetes and that limiting fruit intake has no effect on blood sugar, weight loss, or waist circumference.

While fructose in whole fruits and veggies is unlikely to cause metabolic problems, it can be an issue for some people with digestive disorders. When glucose is present in equal or greater amounts than fructose in a food, as it is in bananas, berries, and cantaloupe, the fructose will be well absorbed (because glucose helps with fructose absorption). However, when there’s more fructose than glucose in a food, as is the case for apples, peaches, and papayas, that additional fructose will linger in the gut, where it is rapidly fermented by bacteria. If you have digestive issues, you may wish to limit foods with more fructose than glucose. Please see
chapter 20
for more information on this.

Fiber is plant matter that is indigestible to humans. There are two types of fiber:
soluble fiber
and
insoluble fiber.
Soluble fiber dissolves in water. It is fermented by bacteria in the colon, and creates a viscous, gel-like substance in the digestive tract. Insoluble fiber does not dissolve in water.
It is not fermented in the colon (with some exceptions), and it adds bulk to the stool. Soluble and insoluble fiber are often lumped together in discussions about the merits of fiber, but their effects on the body are quite different. This has caused confusion and led to dangerous dietary and supplement recommendations.

Many studies suggest that soluble fiber is important for human health. While we can’t digest it, some of the one hundred trillion bacteria that live in the human gut can. Intestinal bacteria “eat” soluble fiber by fermenting it. In the process of fermenting the fiber, the bacteria produce short-chain fatty acids like butyrate, propionate, and acetate. These short-chain fats are the primary energy source for intestinal cells in the colon, and butyrate in particular has been associated with several health benefits. It has anti-inflammatory effects, increases insulin sensitivity, delays the development of neurodegenerative diseases, and has shown promise in the treatment of diseases of the colon such as Crohn’s, IBS, and ulcerative colitis. Butyrate may play a role in healthy metabolic function, stress resistance, and the immune response. In fact, the benefits observed in epidemiological studies of a diet high in naturally occurring fiber are likely due to the higher butyrate production from these diets.

Soluble fiber may also protect against heart disease. Research shows a strong inverse association between dietary fiber intake and heart disease, heart attack, and peripheral artery disease. In one major study, subjects were followed for more than nineteen years, and those who had the highest dietary soluble fiber intake had a 15 percent lower risk of heart disease and a 10 percent lower risk of cardiovascular events than those who had less soluble fiber in their diets. Soluble fiber binds cholesterol, increases the activity of LDL receptors in the liver (which helps clear LDL from the bloodstream), improves insulin sensitivity, and increases satiety (the feeling of fullness), resulting in lower overall calorie consumption.

By contrast, most insoluble fibers (with the exception of resistant starch, which I’ll discuss below) have only partial or low fermentability. Insoluble fibers provide a bulking action and tend to increase regularity, but they do not generate short-chain fatty acids like butyrate and thus don’t have the same health benefits as soluble fibers. While soluble fiber
has been shown to protect against heart disease, insoluble fiber has not. What’s more, excess insoluble fiber can bind to nutrients such as zinc, magnesium, calcium, and iron, preventing their absorption.

The effects of whole-grain fiber (which is mostly insoluble) may be especially harmful. In one study involving men who had previously suffered heart attacks, there were 22 percent more deaths in the high-fiber group (these subjects nearly doubled their grain-fiber intake, going from 9 to 17 grams per day) than in the control group.

Resistant starch is an insoluble fiber with unique properties. Starch exists as large chains of glucose molecules in plants. Since humans produce amylase, an enzyme that breaks down starch, most forms of starch are easily absorbed in the digestive tract. However, resistant starch is unique among starches in that it cannot be broken down in the small intestine and digested by humans. But unlike other types of insoluble fiber, resistant starch can be fermented by gut microbiota in the large intestine to produce helpful short-chain fatty acids like butyrate. Resistant starch has several other benefits, including increasing the uptake of minerals like calcium, boosting levels of
Bifidobacteria
(a beneficial genus of bacteria in the large intestine), reducing harmful pathogens, improving gut motility, and reducing blood-sugar and insulin levels. On a Personal Paleo Code diet, resistant starch is found in unripe bananas, potatoes that have been cooked and cooled, potato starch, plantain flour, tapioca flour, and some legumes (for those who tolerate them). It can also be used as a supplement for those with digestive and/or blood-sugar problems, which I’ll discuss in future chapters.

Fiber is like most nutrients: too little or too much can cause problems. The best approach is to obtain fiber in the context of a whole-foods diet. Though soluble fiber is probably more beneficial than insoluble fiber, many foods in the Paleo diet—such as yams and sweet potatoes, green leafy vegetables, carrots and other root vegetables, fruits with edible peels (like apples and pears), berries, seeds, and nuts—contain both. There’s no need to restrict insoluble fiber when it naturally occurs in these foods (unless you have digestive problems, which I’ll discuss further in
chapter 10
). However, grains are high in insoluble fiber and low in bioavailable nutrients and are best avoided.

Now that you have a better understanding of the different types of carbohydrate and how they are processed in the body, let’s look at the best
dietary sources of carbohydrate from a Paleo perspective. These should form the foundation of your carbohydrate intake during the Step 1 Reset. In Step 2, you may choose to reintroduce moderate amounts of other sources of carbohydrate, such as dairy products, certain grains like white rice and buckwheat, and concentrated sweeteners.

In Step 3, you’ll explore how much carbohydrate is optimal for you based on your activity level, health status, digestive function, and other factors. During Step 1, the focus is on carbohydrate quality: replacing refined grains and sugars with the more nutrient-dense, whole-food carbohydrates listed below.

During the Step 1 Reset you can aim for approximately
15 percent to 30 percent of calories from carbohydrate.
For a moderately active male eating 2,600 calories a day, that comes out to
100 to 200 grams of carbohydrate
per day. For a moderately active female eating 2,000 calories a day, that comes out to
75 to 150 grams of carbohydrate
per day. Those with blood-sugar issues or who wish to lose significant amounts of weight should aim for 10 percent to 15 percent of calories from carbohydrate, which comes out to 65 to 100 grams on a 2,600-calorie diet, or 50 to 75 grams on a 2,000-calorie diet.

Nonstarchy vegetables include cruciferous vegetables (like broccoli and cauliflower), lettuces, winter greens, summer squashes, onions, tomatoes, asparagus, and more. Nonstarchy vegetables are excellent sources of micronutrients and fiber, but overall they are quite low in carbohydrates. Most have fewer than eighty calories of carbohydrates per pound, and those are typically in the form of glucose and fructose. What’s more, some evidence suggests that the human body expends up to forty calories for every pound of nonstarchy vegetables consumed. This suggests a net gain of a mere forty calories per pound of vegetables eaten.

Vegetable
: Artichokes

Measure
: 1 medium

Carbohydrate, G
: 14

Vegetable
: Parsnip

Measure
: 1/2 cup, slices

Carbohydrate, G
: 13

Vegetable
: Rutabaga