Good Carbs, Bad Carbs

By Kris Gunnars

This article originally appeared on HealthLine.com, August 18, 2016.  Used with Permission. 

Carbs are highly controversial these days. The dietary guidelines suggest that we get about half of our calories from carbohydrates. On the other hand, some claim that carbs cause obesity and type 2 diabetes, and that most people should be avoiding them.

 

There are good arguments on both sides, and it appears that carbohydrate requirements depend largely on the individual. Some people do better with a lower carb intake, while others do just fine eating plenty of carbs. This article takes a detailed look at carbs, their health effects and how you can make the right choices.

 

What Are Carbs?

Carbs, or carbohydrates, are molecules that have carbon, hydrogen and oxygen atoms. In nutrition, “carbs” refers to one of the three macronutrients. The other two are protein and fat. Dietary carbohydrates can be split into three main categories:

Sugars: Sweet, short-chain carbohydrates found in foods. Examples are glucose, fructose, galactose and sucrose.

Starches: Long chains of glucose molecules, which eventually get broken down into glucose in the digestive system.

Fiber: Humans can not digest fiber, although the bacteria in the digestive system can make use of some of them.

 

The main purpose of carbohydrates in the diet is to provide energy. Most carbs get broken down or transformed into glucose, which can be used as energy. Carbs can also be turned into fat (stored energy) for later use. Fiber is an exception. It does not provide energy directly, but it does feed the friendly bacteria in the digestive system. These bacteria can use the fiber to produce fatty acids that some of our cells can use as energy. Sugar alcohols are also classified as carbohydrates. They taste sweet, but usually don’t provide many calories.

 

Bottom Line: Carbohydrates are one of the three macronutrients. The main types of dietary carbohydrates are sugars, starches and fiber.

 

“Whole” vs “Refined” Carbs

Not all carbs are created equal. There are many different types of carbohydrate-containing foods, and they vary greatly in their health effects. Although carbs are often referred to as “simple” vs “complex,” I personally find “whole” vs “refined” to make more sense. Whole carbs are unprocessed and contain the fiber found naturally in the food, while refined carbs have been processed and had the natural fiber stripped out. Examples of whole carbs include vegetables, whole fruit, legumes, potatoes and whole grains. These foods are generally healthy.

 

On the other hand, refined carbs include sugar-sweetened beverages, fruit juices, pastries, white bread, white pasta, white rice and others. Numerous studies show that refined carbohydrate consumption is associated with health problems like obesity and type 2 diabetes (1, 2, 3). They tend to cause major spikes in blood sugar levels, which leads to a subsequent crash that can trigger hunger and cravings for more high-carb foods (4, 5). This is the “blood sugar roller coaster” that many people are familiar with.

 

Refined carbohydrate foods are usually also lacking in essential nutrients. In other words, they are “empty” calories.

 

The added sugars are another story altogether, they are the absolute worst carbohydrates and linked to all sorts of chronic diseases (6, 7, 8, 9). However, it makes no sense to demonize all carbohydrate-containing foods because of the health effects of their processed counterparts. Whole food sources of carbohydrates are loaded with nutrients and fiber, and don’t cause the same spikes and dips in blood sugar levels.

 

Hundreds of studies on high-fiber carbohydrates, including vegetables, fruits, legumes and whole grains show that eating them is linked to improved metabolic health and a lower risk of disease (10, 11, 12, 13, 14).

 

Bottom Line: Not all carbs are created equal. Refined carbs are associated with obesity and metabolic diseases, but unprocessed carbohydrate foods are very healthy.

Good Carbs Bad Carbs

Low-Carb Diets Are Great For Some People

No discussion about carbs is complete without mentioning low-carb diets. These types of diets restrict carbohydrates, while allowing plenty of protein and fat. Over 23 studies have now shown that low-carb diets are much more effective than the standard “low-fat” diet that has been recommended for the past few decades. These studies show that low-carb diets cause more weight loss and lead to greater improvement in various health markers, including HDL (the “good”) cholesterol, blood triglycerides, blood sugar, blood pressure and others (15, 16, 17, 18, 19).

 

For people who are obese, or have metabolic syndrome and/or type 2 diabetes, low-carb diets can have life-saving benefits. This should not be taken lightly, because these are currently the biggest health problems in the world, responsible for millions of deaths per year.

However, just because low-carb diets are useful for weight loss and people with certain metabolic problems, they are definitely not the answer for everyone.

 

Bottom Line: Over 23 studies have shown that low-carbohydrate diets are very effective for weight loss and lead to improvements in metabolic health.

 

“Carbs” Are Not The Cause of Obesity

Restricting carbs can often (at least partly) reverse obesity. However, this does not mean that the carbs were what caused the obesity in the first place. This is actually a myth, and there is a ton of evidence against it.

 

While it is true that added sugars and refined carbs are linked to increased obesity, the same is not true of fiber-rich, whole-food sources of carbohydrates. Humans have been eating carbs for thousands of years, in some form or another. The obesity epidemic started around 1980, and the type 2 diabetes epidemic followed soon after.

 

Blaming new health problems on something that we’ve been eating for a very long time simply doesn’t make sense. Keep in mind that many populations have remained in excellent health while eating a high-carb diet, such as the Okinawans, Kitavans and Asian rice eaters.

 

What they all had in common was that they ate real, unprocessed foods. However, populations that eat a lot of refined carbohydrates and processed foods tend to be sick and unhealthy.

 

Bottom Line: Humans have been eating carbs since long before the obesity epidemic, and there are many examples of populations that have remained in excellent health while eating diets high in carbs.

Carbs Are Not “Essential,” But Many Carb-Containing Foods Are Incredibly Healthy

Many low-carbers claim that carbs are not an essential nutrient. This is technically true. The body can function without a single gram of carbohydrate in the diet. It is a myth that the brain needs 130 grams of carbohydrate per day. When we don’t eat carbs, part of the brain can use ketones for energy. These are made out of fats (20).

 

Additionally, the body can produce the little glucose the brain needs via a process called gluconeogenesis. However, just because carbs are not “essential” – that doesn’t mean they can’t be beneficial. Many carb-containing foods are healthy and nutritious, such as vegetables and fruits. These foods have all sorts of beneficial compounds and provide a variety of health benefits. Although it is possible to survive even on a zero-carb diet, it is probably not an optimal choice because you’re missing out on plant foods that science has shown to be beneficial.

 

Bottom Line: Carbohydrates are not an “essential” nutrient. However, many carb-rich plant foods are loaded with beneficial nutrients, so avoiding them is a bad idea.

How to Make the Right Choices

As a general rule, carbohydrates that are in their natural, fiber-rich form are healthy, while those that have been stripped of their fiber are not. If it’s a whole, single ingredient food, then it’s probably a healthy food for most people, no matter what the carbohydrate content is.

With this in mind, it is possible to categorize most carbs as either “good” or “bad” – but keep in mind that these are just general guidelines. Things are rarely ever black and white in nutrition.

Good Carbs:

Vegetables: All of them. It is best to eat a variety of vegetables every day.

Whole fruits: Apples, bananas, strawberries, etc.

Legumes: Lentils, kidney beans, peas, etc.

Nuts: Almonds, walnuts, hazelnuts, macadamia nuts, peanuts, etc.

Seeds: Chia seeds, pumpkin seeds.

Whole grains: Choose grains that are truly whole, as in pure oats, quinoa, brown rice, etc.

Tubers: Potatoes, sweet potatoes, etc.

 

People who are trying to restrict carbohydrates need to be careful with the whole grains, legumes, tubers and high-sugar fruit.

 

Bad Carbs:

Sugary drinks: Coca cola, Pepsi, Vitaminwater, etc. Sugary drinks are some of the unhealthiest things you can put into your body.

Fruit juices: Unfortunately, fruit juices may have similar metabolic effects as sugar-sweetened beverages.

White bread: These are refined carbohydrates that are low in essential nutrients and bad for metabolic health. This applies to most commercially available breads.

Pastries, cookies and cakes: These tend to be very high in sugar and refined wheat.

Ice cream: Most types of ice cream are very high in sugar, although there are exceptions.

Candies and chocolates: If you’re going to eat chocolate, choose quality dark chocolate.

French fries and potato chips: Whole potatoes are healthy, but french fries and potato chips are not.

 

These foods may be fine in moderation for some people, but many will do best by avoiding them as much as possible.

 

Bottom Line: Carbs in their natural, fiber-rich form are generally healthy. Processed foods with sugar and refined carbs are extremely unhealthy.

 

Low-Carb Is Great For Some, But Others Function Best With Plenty of Carbs

There is no one-size-fits-all solution in nutrition. The “optimal” carbohydrate intake depends on numerous factors, such as age, gender, metabolic health, physical activity, food culture and personal preference. If you have a lot of weight to lose, or have health problems like metabolic syndrome and/or type 2 diabetes, then you are probably carbohydrate sensitive. In this case, reducing carbohydrate intake can have clear, life-saving benefits.

 

On the other hand, if you’re just a healthy person trying to stay healthy, then there is probably no reason for you to avoid “carbs” – just stick to whole, single ingredient foods as much as possible. If you are naturally lean and/or highly physically active, then you may even function much better with plenty of carbs in your diet. Different strokes for different folks.

——————————–

This article originally appeared on HealthLine.com, August 18, 2016.  Used with Permission.  Author Kris Gunnars is a nutrition researcher with a Bachelor’s degree in medicine. Evidence-based nutrition is his passion and devotes his career to informing people about it.

 

 

Sources:

  1. Dietary carbohydrates, refined grains, glycemic load, and risk of coronary heart disease in Chinese adults. American Journal of Epidemiology. Yu D; et al.

https://www.ncbi.nlm.nih.gov/pubmed/24008907

  1. Glycemic Index, Glycemic Load, Carbohydrates, and Type 2 Diabetes

Systematic review and dose–response meta-analysis of prospective studies. Diabetes Care. Darren C. Greenwood, PHD; et al.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3836142/

  1. Rice and noodle consumption is associated with insulin resistance and hyperglycae­mia in an Asian population. The British Journal of Nutrition. Zuñiga YL; et al.

https://www.ncbi.nlm.nih.gov/pubmed/24229726

  1. Effects of dietary glycemic index on brain regions related to reward and craving in men. The American Journal of Clinical Nutrition. Belinda S Lennerz; et al.

http://ajcn.nutrition.org/content/early/2013/06/26/ajcn.113.064113.abstract

  1. High Glycemic Index Foods, Overeating, and Obesity. Pediatrics Journal. David S. Ludwig; et al.

http://pediatrics.aappublications.org/content/103/3/e26.short

  1. Dietary sugars and cardiometabolic risk: systematic review and meta-analyses of randomized controlled trials of the effects on blood pressure and lipids. The American Journal of Clinical Nutrition. Te Morenga; et al.

https://www.ncbi.nlm.nih.gov/pubmed/24808490

  1. Energy and fructose from beverages sweetened with sugar or high-fructose corn syrup pose a health risk for some people. Advances in Nutrition. Bray GA

https://www.ncbi.nlm.nih.gov/pubmed/23493538

  1. Sugar-sweetened beverages, weight gain, and incidence of type 2 diabetes in young and middle-aged women. JAMA. Schulze MB; et al.

https://www.ncbi.nlm.nih.gov/pubmed/15328324

  1. Added sugar intake and cardiovascular diseases mortality among US adults.

JAMA Internal Medicine. Yang Q; et al.

https://www.ncbi.nlm.nih.gov/pubmed/24493081

  1. Fruit and Vegetable Consumption and Risk of Coronary Heart Disease: A Meta- Analysis of Cohort Studies. Journal of Nutrition.

Luc Dauchet; et al.

http://jn.nutrition.org/content/136/10/2588.short

  1. Fruit and Vegetable Consumption and Diabetes Mellitus Incidence among U.S. Adults. Preventive Medicine . Earl S. Ford M.D., M.P.H.; Ali H. Mokdad Ph.D.

http://www.sciencedirect.com/science/article/pii/S0091743500907722

  1. Consumption of nuts and legumes and risk of incident ischemic heart disease, stroke, and diabetes: a systematic review and meta-analysis. The American Journal of Clinical Nutrition. Afshin A; et al.

https://www.ncbi.nlm.nih.gov/pubmed/24898241

  1. Association between dietary whole grain intake and risk of mortality: two large prospective studies in US men and women.JAMA Internal Medicine. Wu H; et al.

https://www.ncbi.nlm.nih.gov/pubmed/25559238

  1. Whole grain and refined grain consumption and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis of cohort studies.

European Journal of Epidemiology. Aune D; et al.

https://www.ncbi.nlm.nih.gov/pubmed/24158434

  1. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. JAMA. Gardner CD; et al.

https://www.ncbi.nlm.nih.gov/pubmed/17341711

  1. Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Nutrition & Metabolism

JS Volek; et al.

https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/1743-7075-1-13

  1. Short-term effects of severe dietary carbohydrate-restriction advice in Type 2 diabetes–a randomized controlled trial.Diabetic Medicine Daly ME; et al.

https://www.ncbi.nlm.nih.gov/pubmed/16409560

  1. Long-term effects of a very-low-carbohydrate weight loss diet compared with an isocaloric low-fat diet after 12 mo. The American Journal of Clinical Nutrition. Brinkworth GD; et al.

https://www.ncbi.nlm.nih.gov/pubmed/19439458

  1. The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutrition and Medicine (London)West­man EC; et al.

https://www.ncbi.nlm.nih.gov/pubmed/19099589

  1. Is dietary carbohydrate essential for human nutrition? The American Journal of Clini­cal Nutrition Eric C Westman

http://ajcn.nutrition.org/content/75/5/951.2.long

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s