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Good carbs vs Bad carbs
The currently used classifications of carbohydrates are not very useful in a nutritional sense.
While “complex vs simple carbs” is a useless classification in a nutritional sense, the refined vs unrefined classification still doesn’t answer the crucial question of which carbohydrates are good and which are bad for our health.
A new standardized classification of carbohydrates is needed. However, while we wait for it most of us refer to these two groups as “healthy carbs vs unhealthy carbs” or “good carbs vs bad carbs”.
Nevertheless, which are healthy carbs and which are not, is still disputed even by official sources.
Note: many official sources even now still use confusing terms such as complex carbohydrates.
After gathering extensive data from the most recent scientific documentation on effects of carbohydrates on our body, it became clearer what can be considered good and bad carbohydrates.
Main characteristics of healthy carbs
- Foods that don’t contain refined sugars (added sugars).
- Foods that are whole/unrefined – fiber and other nutrients are not removed;
- Foods that are low in fructose, unless they are whole fruit;
- Foods that have a low Glycemic Load (GL) – do not raise blood glucose levels significantly;
- Foods that are rich in micronutrients;
- Foods that are high in fiber.
The image below shows some examples of foods containing carbs, sorted by:
- Glycemic Load (GL) level (high, medium and low);
- Fructose contents (whole fruit and vegetables that contain fructose are not shown as high in fructose since they have no negative effect on health). (1)
- Whole fruit and vegetables
Fruit and non-tuber vegetables are a great source of carbohydrates.
Carbohydrate containing foods don’t need to be dense in glucose, as potatoes, to be considered a good carbohydrate source.
Although non-tuber vegetables don’t contain as many carbohydrates as starchy plants, they have sufficient amounts to provide sustained energy for the body’s needs.
Vegetables are abundant in fiber and a whole range of micronutrients. They are also rich in phytonutrients, low in simple sugars and starch and have a low GL.
Fruit, similar to vegetables, are rich in fiber, micronutrients and phytochemicals but, in contrast to vegetables, are higher in fructose and glucose.
Since a diet high in fructose is linked to metabolic syndrome and related diseases, there are some concerns about the consumption of fructose from fruit.
Another concern is the amount of glucose in fruit that may raise blood sugar levels.
The good news, however, is that when consumed as a whole food, fruit have not been shown to cause negative health effects.
On the contrary, a diet rich in fruit and vegetables is proven to be very beneficial for health.
Please bear in mind, however, that an excess of fruit in the diet will take the place of other foods which may create a imbalance in the variety of nutrients. As with every other food group, eat fruit in moderation. (read more..) (2)
You can see the list of fructose in fruit here (read more..).
A high daily consumption of vegetables and fruits is associated with the reduced risk of some of the most serious diseases such as hypertension, coronary heart disease (CHD), stroke, type 2 diabetes, osteoporosis, asthma, certain eye diseases, dementia and colon cancer.
Smoothies, unlike juices, retain their fiber contents together with most of the micronutrients. Think of smoothies as whole vegetables/fruits in a liquid form.
Green smoothies are the best option since they contain a minimal amount of sugar, are low in calories and very rich in fiber and micronutrients.
Although the vitamin levels in smoothies may be slightly diminished through the process of oxidation, during blending or crushing (depending on the equipment), they are still present in high amounts.
Smoothies are low in sugars and in fructose and have a low GL. They are a great addition to our diet and can be treated as whole vegetables and fruits. Depending on the ingredients, they can substitute for meals, such as breakfast or snacks.
Legumes: beans, peas and lentils are a great source of carbohydrates, protein, fiber, vitamins and minerals. They contain no, or insignificant, amounts of fructose, are low in sugar and have a low GL. (6),Beans also have health promoting substances, such as saponins, that are associated with the protection against cancers, by affecting the immune system, lowering cholesterol levels, decreasing blood lipids and lowering blood glucose response. (7)
- Vegetable juices
Vegetable juices are a much better choice than fruit juices. They are generally low in calories, lower in sugar than fruit juices, have a low GL due to low carb contents and a low amount of fructose.
Although vegetable juices have most of the fiber removed, they are a good source of hydration and are still rich in micronutrients and phytochemicals.
As in the case of any food, through processing some small amounts of vitamins may be lost, through oxidation, and the fiber removed.
Vegetable juices (especially green juices) belong to the healthy carbs category and can be included as a complement to a balanced diet.
They are a great way of topping up our body with micronutrients, phytochemicals and antioxidants, Vegetable juices are also a good source of hydration.
Unlike smoothies, they should not be treated as a meal. This is because they are low in fiber and other satiating substances (e.g. protein).
Healthy carbs, but in moderation
- Dried fruit
Dried fruits contain, by weight, about 3.5 more nutrients than fresh fruits. Such a condensed amount of nutrients, such as fiber, micronutrients and antioxidants, makes a small serving a very valuable addition to a healthy diet.
Since carbohydrates are a part of these condensed nutrients, it is important to eat dried fruit in moderation.
Eating large amounts of dried fruit contributes extra calories, may have an impact on blood sugar levels and contributes a high amount of fructose, depending on the type and the amount of the fruit eaten.
One to two ounces of dried fruit per serving (depending on the type of fruit) can be considered as a healthy choice. (read more..)
- Nuts and seeds
Nuts and seeds are very nutritious, and an excellent source of complex carbohydrates. Since they are also high in energy, nuts and seeds should be eaten in moderation.
Nuts are high in complex carbohydrates, fiber, monounsaturated fats, omega 3 fatty acids, vitamin E, plant sterols and L-arginine.
Please note that despite their high caloric value, nuts may be helpful in weight loss.
Seeds are an excellent source of energy, fiber, mono and polyunsaturated oils, protein and various minerals and vitamins.
- Tuber vegetables
Tuber vegetables contain a medium to high amount of starches depending on the tuber type (e.g. potato vs sweet potato).
There are also many health benefits of tubers which vary greatly in their nutrient contents depending on the tuber type.
For instance, on average, sweet potatoes are much richer in fiber, vitamins and minerals, and have a lower GL than potatoes and are a much healthier choice in the starch food group than common potatoes.
If you don’t suffer from diabetes type 2, are not overweight or obese and lead an active life, a small amount of tubers (especially those rich in micro-nutrients and fiber) added to the balanced diet is beneficial.
If your goal is to lose weight or suffer from diabetes, it is best to limit or avoid tuber vegetables due to their impact on blood glucose levels and high calories. (read more..)
- Unrefined (whole) cereal grains
While refined grains can be considered as empty calories, since they are mainly a source of glucose (in a form of starch), stripped of most fiber and micronutrients, whole grains contain some micronutrients and are a great source of fiber and are often referred to as “good carbs”.
Cereal grains, however, are energy dense foods and their most abundant nutrient is glucose (starch). This may present a problem for people who are having trouble with weight control or are diabetic.
Cereal grains and grain products, whether whole or refined, have medium to high GL, which means that for sedentary people having large amounts of pastas, breads, or rice will make it more difficult to lose or control weight.
Grains are also calorie dense since the bulk of the nutrients are carbohydrates.
Grains should be treated the same as other starchy products, such as tuber vegetables, and generally eaten in small amounts.
In some cases, when being overweight and wanting to lose weight or with diabetics, the consumption of these products should be limited to a minimum or completely eliminated from the diet.
Micronutrients present in cereal grains are also present in high quantities in other foods, so by limiting this food group a wide range of plant food can substitute for grains.
Although many studies show that people who add whole grains in their diet have a lower mortality rate and a lower risk of coronary artery disease, they don’t compare with those who instead of grains eat more vegetables, nuts and seeds.
They are more comparable with those who are on nutrient poor diets, eat junk food, or refined carbs. (1)
It is true that when I substitute white rice with brown rice or bar of chocolate with a wholemeal sandwich there will be improvement in my health, and this is what these studies show.
More studies are needed, however, to show what happens if we substitute whole grains rich in carbohydrates and high in Glycemic Load with more vegetables, nuts, seeds and legumes.
This way we would get not only the same nutrients as in whole grains but more variety and with less effect on blood glucose.
Milk is considered a source of protein but it is also another source of carbohydrates. One glass of milk (255ml) contains about 13g of carbohydrates in the form of galactose (lactose + glucose).
There has been some controversy about milk causing all sorts of health problems, such as osteoporosis. However, scientific evidence shows the opposite. (read more..)
If you are not allergic to milk protein and are not sensitive to lactose, milk is a great addition to the diet for its high nutrient content, involvement in promoting bone health, and as a source of energy.
Note on lactose tolerance: the majority of the world’s population has some limit of how much milk they can drink in one sitting before they start feeling bloated. We all have a different tolerance to lactose depending on how much lactase (lactose breaking enzyme) we are able to produce.
That is largely dependent on the origin of our ancestors. (read more..). If a glass of milk gives you an upset stomach, reduce it to half a glass and see if you feel any different.
The bottom line is that intake of milk is restricted to how many enzymes we can produce and, therefore, is usually consumed in moderation.
Bad carbs to avoid
- Refined sugars – high fructose sweeteners and sweetened products
High fructose sweeteners, sugar and any products with a high content of these sweeteners, are the unhealthiest foods and should be avoided or drastically limited.
They include refined sugars such as table sugar (sucrose), agave syrup, high fructose corn syrup (HFCS), maple syrup, candy, ice cream, sweet pastries, cakes, cookies (biscuits) and sodas (soft drinks).
The main characteristic of this group is a high Glycemic Index, high Glycemic Load, high calories and high fructose contents.
- Refined cereal grains
Refined cereal grains have had the fiber and most minerals and vitamins removed during processing. Examples are white bread, white pasta, breakfast cereals, or white rice.
They are basically high in calorie starches (with a small amount of protein). This means that refined cereal grains are collections of glucose molecules with a high Glycemic Index and Glycemic Load, which increases the risk of insulin resistance, metabolic syndrome and type 2 diabetes. (10)
Diets high in refined grains are usually low in fiber and diets low in fiber are associated with colon cancer, heart disease, obesity and type 2 diabetes. (11)
Chose moderate amounts of whole grain products over refined grains, whenever possible.
To put it simply honey, in terms of fructose and GL impact, is almost the same as sugar. The argument that it is a natural product or that it contains some small percentages of other nutrients makes it slightly, but insignificantly better that sugar.
Most of these nutrients are in such small quantities that they don’t even appear when a standard serving is calculated. (read more..)
When referring to the impact of fructose and GL, however, it makes no difference if you use honey or sugar as a sweetener. (12)
- Fruit juices
Fruit juices have a high concentration of fructose and are of medium to high GL, depending on the amount of the juice and the fruit type.
While eating one whole orange has many health benefits due to its rich contents of nutrients and manageable amount of fructose, a cup of juice extracted from 4 oranges has only a tiny amount of fiber, is depleted of some micronutrients, and contains 4 times the amount of sugar (including fructose) than the whole orange.
Although fruit juices are still rich in vitamins and minerals, they have a similar sugar composition to a soft drink and present identical health risks related to high fructose and medium to high GL. (read more..)
NUTRITION FACTS VS NUTRITION MYTHS
You will find a summary of the most common nutrition myths and evidence-based nutrition facts here.