Are carbs healthy or unhealthy? Here’s the simple truth

If you are interested in healthy nutrition, you may have come across this question: Are carbs healthy?

This article addresses the question whether carbohydrates are healthy or not. Before doing that, let’s understand what carbs are.

From a nutrition standpoint, it’s common practice to look at foods from two different standpoints:

  • Macronutrients (carbohydrates, proteins and fat) and micronutrients (vitamins, minerals)
  • and other “food groups” (like vegetables, grains, meat, fish, oils, etc.).

Macronutrients are nutrients that normally come in large amounts and are usually measured in grams.

Micronutrients are present in foods in much smaller amounts and are often measured in milligrams or even micrograms.

What are carbohydrates?

The most common forms of carbohydrates are:

Carbohydrates are present in a large variety of both healthy and unhealthy foods, and play a very important role by providing the body with glucose, which is converted into energy that supports various functions in the body and fuels physical activity.

Some types of carbohydrate are healthier than others.

The healthiest carbs are whole grains, vegetables, fruits, and legumes

The healthiest sources of carbohydrates are unprocessed or minimally processed whole grains, vegetables, fruits, and legumes, that also provide vitamins, minerals, fiber, and phytonutrients.

Unhealthier sources of carbohydrates are as white bread, pastries, french fries, sugary beverages, and other highly processed or refined foods

Unhealthier sources of carbohydrates include white breads, pastries, french fries, sugary beverages, and other highly processed or refined foods that promote diabetes and heart disease and may contribute to weight gain.

When we eat food rich in carbohydrates, our body converts the digestible ones into sugar, which enters in the blood stream.

When blood sugar levels rise, the pancreas produces insulin, a hormone that signals cells to absorb blood sugar that can be used for energy or storage, and so levels of sugar in the bloodstream begin to fall.

At this point, the pancreas starts producing glucagon, a hormone that prompts the liver to start releasing stored sugar.

This balance between pancreas-produced insulin and glucagon makes sure that our cells, in particular brain cells, have a steady supply of blood sugar.

Glycemic index

Historically, carbohydrates have been classified as being either “simple” or “complex”.

Simple carbohydrates are made of sugars like fructose and glucose that have simpler chemical structures and are composed of only one sugar (monosaccharides) or two sugars (disaccharides). These simple carbs are quickly converted into energy by the body, often causing a fast spike in blood sugar and insulin secretion from the pancreas. 

Complex carbohydrates have more complex chemical structures, made by three or more sugars linked together, known as oligosaccharides and polysaccharides. Many complex carbohydrate foods contain fiber, vitamins, minerals, and phytonutrients, and they take longer to digest, which means they have a slower effect on rising blood sugar. Most of the time complex carbohydrates come with these other health promoting nutrients, but in some other cases, they can contain little fiber and other beneficial nutrients, like in white bread and white potatoes.

To explain how different foods affect blood sugar, the glycemic index was created to rank foods based on how quickly and how much they raise blood sugar levels after eating.

If the glycemic index is high, like in sugar or in white bread, carbohydrates are rapidly digested and cause great fluctuations in blood sugar.

When the glycemic index is low, like with whole oats, carbohydrates are digested more slowly, causing a slower rise in blood sugar.

The glycemic index is based on a scale from 0 to 100:

  • low-glycemic foods have a rating of 55 or less
  • medium-level between 56 and 69
  • high-glycemic food between 70 and 100

Glycemic load

The glycemic index is only telling how fast foods raise blood sugar levels, but it does not tell us anything about the total amount of carbohydrates they deliver. For this reason the glycemic load was invented, calculated by multiplying the food’s glycemic index by the amount of carbohydrate it contains.

Typically, a glycemic load:

  • of less than 10 is low
  • from 11 to 19 is medium
  • and of more than 20 is high

So, are carbs healthy?

When it comes to carbohydrates-rich food, in order to promote good health you should prioritize foods that have lower glycemic index and low glycemic loads.

In simpler words, you have to avoid or limit the consumption of refined and highly processed foods, like sugar, white bread, white rice and refined grains in general, french fries, sodas, and alike, and prioritize unprocessed or minimally processed whole grains, vegetables, fruits, and beans.

What foods are good carbs to eat?

Low glycemic index foods

Eating low glycemic food helps control type 2 diabetes, support weight loss and may offer anti-inflammatory benefits. On the other hand, high glycemic foods can lead to an increased risk for type 2 diabetes, heart disease, overweight, age-related macular degeneration, ovulatory infertility, and colorectal cancer. Find more information on the Harvard T.H. Chan School of Public Health website.

Many studies have demonstrated a correlation between higher dietary glycemic index and increased risk of type 2 diabetes and coronary heart disease. Less studies have investigated the correlation between glycemic index and body weight, which remains controversial. In any case, even if your weight is normal, if your nutrition is based on high glycemic index foods then you are still exposed to health risks.

There are several factors influencing the glycemic index of food. Processed food, like refined grains that have been deprived of their bran and germ, have a higher glycemic index than whole grains because they are digested quicker. For the same reason, finely ground grains have higher glycemic index than coarsely ground grains, so eating whole grains like brown rice or oats may be healthier than eating processed whole grain bread.

In general, foods that are high in fiber have a slower digestion rate and therefore a lower glycemic index.

Ripe fruits and vegetables normally have a higher glycemic index than un-ripened fruit (but this does not mean that you have to eat them un-ripened!) and meals that include fat or acid foods have a lower glycemic index.

Harvard Medical School has created a list of the glycemic index for the most common foods and the University of Sydney in Australia offers a free online service to search within a database of foods and their glycemic indices.

Low glycemic load foods

Clinical research indicates that people who consume lower-glycemic load diets have a lower risk of developing type 2 diabetes than those who eat a diet of higher-glycemic load foods, and higher-glycemic load diets are associated with an increased risk for coronary heart disease events. The Harvard T.H. Chan School of Public Health, has published a list of low, medium, and high glycemic load foods.

What is high in carbs but healthy?

In general, high-carbs foods that have a low or medium glycemic index, so a glycemic index lower than 69, are healthier carbs compared to carbs with high glycemic index (>70).

Having said that, only focusing on individual foods may be misleading. In fact, the insulin response in our blod stream when eating a meal depends not only on the glycemic index of the individual foods, but also on how these foods are combined together.

This interesting study “Post-prandial glucose and insulin responses of hummus alone or combined with a carbohydrate food” provides insulin response data relative to eating white bread alone, chickpeas hummus alone, and white bread together with chickpeas hummus.

White bread has a very high glycemic index, this means that it causes a rapid increase of blood insulin after eating it. Chickpeas hummus, instead has a very low glycemic index, so it causes a slow increase of insulin levels in the blood.

The study compared the insulin response after eating 50g of white bread alone and after eating 50g of white bread with different amount of hummus on it. The findings show very clearly that adding hummus on bread flattens the insulin response, effectively lowering the glycemic index compared to eating white bread alone.

In other words, eating 50g of white bread plus about 100g of hummus, may be healthier than eating 50g of white bread alone because it flattens both the insulin and glucose response in the blood.

The good news is that following the usual recommendations of eating regularly whole grains, vegetables including healthy vegetable fats like olive oil, fruits, nuts and seeds, and fermented foods and drinks, helps keeping the glycemic index under control.

Which carbs food are good for weight loss?

If you are on a journey to lose weight, the recommendation is to prioritize healthy carbs foods that have a low glycemic index and still keep the healthy eating guidelines presented in the previous chapter: prioritizing whole grains, vegetables (including healthy vegetable fats like olive oil), fruits, nuts and seeds, and fermented foods and drinks.

Can I lose weight and still eat carbs?

Within the recommendations above to prioritize healthy carbs with low glycemic index and load, you can definitely eat carbs and lose weight as far as the amount of calories you eat are less than the amount calories you burn. You may also consider eating a bit less carbs and a bit more healthy proteins and fats. Don’t forget to include white meat, eggs, fish, dairy, legumes, soy products, and mushrooms in your eating plan.

Take a look at our free weekly meal planner for healthy eating to help you building your meal plan.

Which carbs to avoid?

If you have healthy eating habits you will not need to strictly avoid any type of foods. Having said that, it’s a good idea to limit as much as possible foods with a high glycemic index, in particular when consumed alone. These type of carbs are

  • simple sugars, for example sugary beverages such as sodas and fruit juices
  • unrefined grains, such as products made from white flour like white breads and pasta, and white rice
  • peeled potatoes

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The healthiest carbs are whole grains, vegetables, fruits, and legumes (image generated by me with Midjourney AI)