Sunday, April 20, 2008

High-Quality Carbs, Proteins, and Fats

What are the healthiest foods in the world?  The quality of carbohydrates, proteins and fats can vary a great deal.  As part of my research of the Zone diet, this post summarizes lessons learned around high-quality carbohydrates, high-quality proteins, and high-quality fats.  This post is based on the book, The Top 100 Zone Foods: The Zone Food Science Ranking System , by Dr. Barry Sears.

High-Quality Carbohydrates (Think Anti-Oxidants)
Dr. Sears writes that the key to high-quality carbohydrates is to think anti-oxidants:

My definition of high-quality carbohydrates is one that does two things: (1) provides anti-oxidants and (2) keeps your blood sugar and insulin levels as stable as possible.  Anti-oxidants are essential because they quench free radicals, those unstable molecules in your body that wreak havoc on healthy cells and tissues.  Excess free-radical production remains the biggest impediments to your quality of life.  Although you need some free radicals to transform food into energy, any excess production of them (caused by eating too much food in general) triggers a breakdown in all areas of your body.  Free radicals degrade your cellular DNA, which can turn a healthy cell into a cancerous one.  They can also cause inflammation leading to heart disease, arthritis, and even wrinkles.

Three Factors to High-Quality Carbs
Dr. Sears considered three factors to determine the top-quality carbohydrates for his Top 100 Zone Foods list:

  • Factor #1: anti-oxidative capacity.
  • Factor #2: Glycemic index.
  • Factor #3: Soluble fiber content.

Factor #1: Anti-Oxidant Capacity
Dr. Sears looks for carbohydrates with high anti-oxidant capacity:

When calculating the highest-quality carbohydrates for my Top 100 list, I looked first at fruit's or vegetable's total anti-oxidative capacity per gram of carbohydrate.  This includes not only the essential anti-oxidants such as vitamin A (often in the form of beta-carotene) and vitamin C, but also the braod array of nonessential anti-oxidants (like lycopene and other phytochemicals) that are packed into each gram of carbohydrate.  Anti-oxidant capacity is based on the strength that a certain food has to neutralize a given number of free radicals.  I ranked fruits and vegetables based on their anti-oxidant capacity per gram of carbohydrate.

Factor #2: Glycemic Index
Dr. Sears looks for carbohydrates with a lower glycemic index and lower glycemic load:

This is a measure of how rapidly your body breaks down carbohydrates in a particular food into the simple sugar glucose and how quickly this glucose gets into your bloodstream.  The faster a carbohydrate gets into your bloodstream, the faster the rise in your blood sugar and the faster the insulin is secreted to drive this excess glucose into storage in the muscle and liver.  The concept of the glycemic index only became well known during the past decade as nutritionists began to realize that many politically correct complex carbohydrates, like potatoes, actually caused faster rises in blood sugar than, well, table sugar.  The more rapidly the blood sugar increases, the more insulin is released.

Factor #3: Soluble Fiber
Dr. Sears looks for high soluble fiber in his carbohydrates:

This is the last factor I use to determine whether or not a carbohydrate is top Zone food.  Soluble fiber slows down the rate of entry of carbohydrates into the bloodstream, and this reduces insulin stimulation.  This factor can move some of the relative losers on the anti-oxidative index into winners.  This is the saving grace for apples, oatmeal, barley, and beans, which are relatively low in anti-oxidative capacity,but high in soluble fiber.  To qualify for the Top 100 Zone Foods list, a carbohydrate should have at least 0.3 grams of soluble fiber per Zone Block of carbohydrate.

Excellent Carbohydrates
According to Dr. Sears, the following are excellent Zone carbohydrate sources.  The number in parentheses is the anti-oxidative capacity per gram of carbohydrate.  Higher is better.

Vegetables

  • (841) Spinach
  • (434) Kale
  • (387) Romaine lettuce
  • (254) Broccoli
  • (227) Cauliflower

Fruits

  • (473) Blueberries
  • (398) Blackberries
  • (273) Strawberries

Very Good Carbohydrates
According to Dr. Sears, the following are very good Zone carbohydrate sources.  The number in parentheses is the anti-oxidative capacity per gram of carbohydrate.  Higher is better. 

Vegetables

  • (159) Eggplant
  • (146) Brussels sprouts
  • (131) Red pepper
  • (95) Cabbage
  • (69) String beans
  • (56) Onion

Fruits

  • (101) Plum
  • (63) Pink Grapefruit
  • (62) Tomato
  • (51) Kiwi

Good Carbohydrates
According to Dr. Sears, the following are good Zone carbohydrate sources.  The number in parentheses is the anti-oxidative capacity per gram of carbohydrate.  Higher is better.

Vegetables

  • (37) Yellow squash
  • (36) Celery
  • (30) Cucumber

Fruits

  • (44) Pear
  • (42) Orange
  • (42) Red grapes
  • (30) Green grapes

Exceptionally Useless Carbohydrates
According to Dr. Sears, the following have virtually no anti-oxidative capacity:

  • Bagels
  • Pasta
  • Rice
  • Bread

High-Quality Protein (Think Low Fat)
According to Dr. Sears, the key to high-quality protein is to think low fat:

I define the quality of a protein source by its fat content.  Realize that all protein (even tofu) contains fat.  To quality for my Top 100 Zone Foods list, a protein choice must contain at least twice as much protein as fat.  This eliminates most cuts of beef, pork, and lamb, with a few exceptions like well-trimmed beef tenderloin.  Switching from high-fat protein choices to lower-fat ones will reduce your intake of saturated fat.  This will not only decrease cholesterol levels but also make the insulin receptors in your cells more responsive to insulin so that your body needs to make less of this hormone.  At the same time, you'll also splash your intake of health-damaging Omega-6 fatty acids, a type of polyunsaturated fat found in all sources of protein.  This type of fat serves as the building block for certain types of eicosanoids that can accelerate the development of heart disease, cancer, Type 2 diabetes, and arthritis.

Excellent Protein
According to Dr. Sears, the following are excellent Zone protein sources.  The number in parentheses is the Zone protein quality.  The higher the number the better.

  • (44) Mackeral
  • (40) Turkey breast
  • (30) Haddock
  • (30) Cod
  • (30) Salmon
  • (25) Soybean hamburger crumbles
  • (22) Tuna steak
  • (22) Turkey breast, deli
  • (21) Lobster
  • (20) Sea bass
  • (20) Snapper

Very Good Protein
According to Dr. Sears, the following are very good Zone protein sources.  The number in parentheses is the Zone protein quality.  The higher the number the better. 

  • (18) Chicken breast
  • (16) Freshwater bass
  • (15) Trout
  • (12) Cottage cheese (1%)
  • (9) Chicken breast, deli
  • (9) Tuna, canned in water
  • (7) Soy imitation meat products
  • (6) Emu

Good Protein
According to Dr. Sears, the following are good Zone protein sources.  The number in parentheses is the Zone protein quality.  The higher the number the better. 

  • (4) Pork tenderloin, well-trimmed
  • (4) Tofu, extra-firm
  • (3) Beef tenderloin, well-trimmed
  • (3) Tofu, firm
  • (2) Tempeh
  • (2) Tofu, soft

Low-Quality Protein
According to Dr. Sears, these are low-quality protein foods.  They are fatty beef and pork products that contain relatively high amounts of fat and therefore high amounts of saturated and Omega-6 fats.

  • (0.6) Ground beef (27% fat)
  • (0.3) Sausage
  • (0.2) Bacon

High-quality Fat: Think Monounsaturated Fat
According to Dr. Sears, the key to high-quality fat is to think monounsaturated fat:

Although I expend many more words discussing carbohydrates and protein, fat is not just a footnote.  It's just as critical a part of the Zone.  This is because high-quality fat will definitely fuel you better than low-quality fat.  I define as high quality food that's high in monounsaturated fats and low in saturated and Omega-6 fats.  Saturated fat (found in whole milk dairy products and fatty red meat) can raise cholesterol levels, which leads to heart disease.  Omega-6 fats, as mentioned above, can have adverse effects on the overproduction of "bad" eicosanoids associated with chronic disease.  Monounsaturated fats, on the other hand, have no effect on insulin, cholesterol, or eicosanoids.  Some research suggests that they may even raise "good" (high-density lipoprotein, or HDL)) cholesterol levels.  As a result, populations that consume high levels of monounsaturated fat have very low levels of cardiovascular disease and improved longevity.

Excellent Quality Fats
According to Dr. Sears, the following are excellent quality fats.  The number in parentheses is the Zone fat quality.  The higher the number the better.

  • (4.5) Macadamia nuts
  • (3.6) Olive oil
  • (3.5) Olives

Very Good Quality Fats
According to Dr. Sears, the following are very good quality fats.  The number in parentheses is the Zone fat quality.  The higher the number the better.

  • (2.3) Avocado
  • (2.2) Canola oil
  • (2.2) Almond butter
  • (2.0) Almonds

Good Quality Fats
According to Dr. Sears, the following are good quality fats.  The number in parentheses is the Zone fat quality.  The higher the number the better.

  • (1.6) Cashews
  • (1.1) Peanuts

Poor-Quality Fats
According to Dr. Sears, the following are poor-quality fats:

  • (0.9) Lard
  • (0.4) Butter
  • (0.2) Safflower oil
  • (0.2) Soybean oil

You Can Choose How You Feel
According to Dr. Sears, you can choose to hold the reigns and control your hormones by choosing Zone meals:

Consume one Zone meal after another, and you will achieve consistent hormonal control for your lifetime.  Use low-quality foods on the other hand, and you will simply lose the reigns and allow your hormones to run wild.  The choice should be easy to make.

Key Take Aways
While I'm not surprised by the data, I do like the precision and clarity that the food ranking creates.  Here's my key take aways:

  • For high-quality carbs, think anti-oxidants.  High-quality carbohydrate sources have high anti-oxidative capacity, low glycemic impact, or high soluble fiber content.
  • For high-quality protein, think low fat.   This is probably the first time I've actually seen a crisp breakdown of why to choose low-fat over high-fat protein.  Choosing proteins that have twice as much protein as fat has the compound effect of lowering your intake of saturated fat, cutting your intake of Omega-6  fatty acids, decrease your cholesterol levels, and  make the insulin receptors in your cells more responsive to insulin so that your body needs to make less of this hormone.  Impressive.
  • For high-quality fat, think monounsaturated.   Saturated fat can raise cholesterol levels.  Monounsaturated fats have no effect on insulin, cholesterol, or eicosanoids, and potentially raise "good" cholesterol levels.   
  • Choose your foods based on quality.  I really like knowing the caliber and impact of my food choices.  I only had a vague idea of food quality based on simple rules like choosing fibrous carbs over starchy carbs, and choose deeper, darker colored vegetables over lighter ones.

My Related Posts

2 comments:

Ramsey said...

Great article!

High fiber foods, like Miracle Muffins
http://www.miraclemuffins.com
are a great way to help manage diabetes, lower cholesterol and aid with weight loss!

J.D. Meier said...

Thanks Ramsey -- good point on the fiber. I see it consistently recommended as a key to good health.