New research defines the difference between good carbs & bad carbs

good-carb-bad-carbThe controversy over the role carbohydrates play in a healthy diet rages on; government recommendations indicate we should eat about half our calories in carbs, while some health authorities insist carbs lead to type 2 diabetes and obesity.

The truth is, there’s no hard and fast rule for the simple reason that we’re all individuals; some people do fine eating plenty of carbs, while others don’t.

The real question turns out to be the source of carbs, because all carbs don’t affect our metabolism or health in the same way.

Let’s take a look at the complex question of carbohydrates, including which ones are good and which ones are bad.

Carbohydrates 101

The three macronutrients in food are protein, fat and carbohydrates. Carbohydrate molecules are made up of oxygen, hydrogen and carbon.

Carbs are further subdivided into three categories:

  1. Sugars are the sweet, short-chain carbs such as fructose, galactose, glucose and sucrose.
  2. Starch molecules are arranged in a long chain.
  3. Fiber feeds the bacteria in our gut, but the body cannot digest it.

Carbs are broken down into glucose, which provides energy for the system; if it’s not required at the time, it is stored as fat.

Fiber doesn’t yield energy, but when bacterium feed on it, the resulting fatty acids can be used by some body cells for energy.

Foods containing carbs are often designated as either complex or simple, but another way to look at it is whether they are whole or refined.

Refined carbohydrates have been stripped through processing of naturally occurring fiber, whereas whole carbohydrates are just that: whole, complete with all the nutrients and fiber originally present.

Fresh fruits and vegetables, along with whole grains and legumes, are examples of whole carbohydrates; white bread, white rice, white pasta and pastries are refined, as well as sugary drinks and fruit juice.

Eating refined carbs like those listed above is associated with a higher risk of developing type 2 diabetes and obesity, as well as other chronic diseases. (1, 2)

Blood sugar spikes after eating refined carbs, followed by a crash that often leads to hunger and intense cravings for more high-carb foods. (3)

These are the well-known empty calories, delivering virtually no nutrients; however, it’s not sensible to condemn whole foods containing carbs and important nutrients just because their refined counterparts spike blood sugar and wreak havoc on the metabolism. (4, 5)

Studies on the effects of carbohydrate-rich, whole foods on health clearly show that the risk of many chronic diseases is dramatically decreased when these foods are included in the diet, and metabolic health is improved. (6, 7, 8)

The Popularity of Low-Carb Diets

Besides positive effects on overall health, low-carb diets are well-known as a successful way to lose weight. (9, 10, 11)

Millions of people suffering from obesity, type 2 diabetes and other metabolic disorders die from these diseases worldwide every year. For these individuals, following a low-carb diet can be truly life-saving, but low-carb diets don’t work well for everyone.

While restricting carbohydrates can be effective in reversing obesity, evidence indicates that eating carbs doesn’t actually cause obesity.

Specifically, eating whole, natural foods rich in fiber and carbohydrates does not lead to obesity.

These foods have nourished humans since the dawn of time, while the obesity epidemic began in the 1980s, followed by the type 2 diabetes epidemic.

It makes no sense to blame these growing health issues on the high carbohydrate foods that have been integral to the development of various populations for thousands of years. The rice-based diet of Okinawans, who have a high number of healthy centenarians among their elders, is a perfect example.

But such staples were historically consumed in their natural and unprocessed state. Populations who eat refined carbohydrates tend to grow fat and generally unhealthy.

It’s not essential to consume carbohydrates for fuel; the body uses other sources of energy when carbs aren’t available, such as ketones made from fat. (12)

The small amount of carbs necessary for proper brain function can be obtained through a process known as gluconeogenesis. But just because humans can live without carbohydrates doesn’t mean they don’t have many beneficial health effects.

Good vs. Bad

As a general rule, if a food is whole and has not been processed and stripped of fiber or nutrients, it should be healthy for most people.

The following list gives examples of how this generalization would apply to making dietary choices in everyday life:

Good Carbs

  • Vegetables – eat as much variety as you can every day
  • Whole fruits
  • Legumes, like kidney beans, peas and lentils
  • Nuts, such as walnuts, almonds, and hazelnuts
  • Seeds, like sunflower, chia, and pumpkin
  • Whole grains, such as brown rice, oats, or quinoa
  • Tubers, like potatoes and yams

If you’re following a low-carb diet, you can still eat these foods in small amounts; it may be necessary to forgo super-sweet fruits and stick with lower-carb selections, like blueberries and grapefruit.

Bad Carbs

  • Sweetened drinks, such as sugary soda or fruit juice
  • White bread and most commercially-made breads
  • Cookies, pastry and cake
  • Ice cream (low-sugar varieties can be less problematic)
  • Candy and chocolate, except for dark chocolate, which is usually low in sugar
  • Potato chips and French fries

Some people do well eating foods listed in the “bad carb” group in moderation, while others suffer ill effects even with small amounts.

The Bottom Line

Optimal carbohydrate intake is best determined on an individual basis.

Not only is personal preference a factor, but cultural customs, gender, age, levels of physical activity and existing metabolic health all need to be taken into consideration.

Those who are extremely active can thrive on a high-carb diet, satisfying the body’s needs with a steady source of fuel.

Anyone who is significantly overweight or dealing with metabolic problems or type 2 diabetes is likely sensitive to carbohydrates, and may be able to make significant health improvements through limiting intake.

For people who are just looking to make smart food choices, sticking with whole foods rich in carbohydrates and vital nutrients is usually both acceptable and beneficial.

Summary: Carbs have been a source of ongoing controversy partly because we’re not all the same despite obvious similarities. Stay away from refined carbohydrates and figure out which level of intake works best for you to cultivate good health.

References:

  1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3836142/
  2. http://www.ncbi.nlm.nih.gov/pubmed/24229726
  3. http://ajcn.nutrition.org/content/early/2013/06/26/ajcn.113.064113.abstract
  4. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3836142/
  5. http://www.ncbi.nlm.nih.gov/pubmed/24229726
  6. http://jn.nutrition.org/content/136/10/2588.short
  7. http://www.sciencedirect.com/science/article/pii/S0091743500907722
  8. http://www.ncbi.nlm.nih.gov/pubmed/24898241
  9. http://www.ncbi.nlm.nih.gov/pubmed/17341711
  10. http://nutritionandmetabolism.biomedcentral.com/articles/10.1186/1743-7075-1-13
  11. http://www.ncbi.nlm.nih.gov/pubmed/16409560
  12. http://ajcn.nutrition.org/content/75/5/951.2.long
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