Carbohydrates are controversial among those who are trying to lose weight. Because individual carbohydrate needs are unique, this informative guide will help to optimize carbohydrate consumption and provide healthier options regardless of fitness goals.
Carbohydrates are found in almost all foods and provide four calories per gram. Not all carbohydrates are created equal as different carbs affect the body differently. Carbohydrate-containing foods generally have a combination of two types: simple and complex.
Simple carbs are also known as “sugar.” It is made of up to two sugar building blocks connected in a chain. The building blocks can be glucose, fructose and galactose. Because the chains are short, they are easy to break down, which is why they taste sweet when they hit the tongue. They are also digested and absorbed into the bloodstream quickly.
Foods high in simple carbohydrates include sweeteners (table sugar, syrup, honey), candy, jellies and jams and refined flour. Fruits, vegetables, beans and dairy contain simple carbs, too, but they come with vitamins and minerals, plus fibre and/or protein, so they are healthier choices.
Complex carbs can be either “starch” or “fibre.” This carbohydrate is made of three or more sugars connected in a chain. They also contain fibre and tend to come in foods that contain protein and/or healthy fats, as well as vitamins and minerals. They use the same sugar building blocks as simple carbs, but the chains are longer and take more time to break down, which is why they don’t taste as sweet.
The longer chains also slow digestion and thus the absorption of the monosaccharides all carbs are broken down into. This results in a more gradual insulin response, as well as increased satiety. Foods high in complex carbohydrates include bread, rice, pasta, beans, whole grains and vegetables.
Fibre is a carbohydrate, but it doesn’t contribute much to calories because it can’t be broken down and absorbed into the body. Fibre helps to maintain bowel health, lowers cholesterol, can lower the risk of diabetes and other health benefits. There are two types of fibre, soluble and insoluble.
Just looking at a nutrition label, you will see “dietary fibre” and “sugar” listed under “total carbohydrates,” but the grams never add up. That’s because “total carbohydrates” includes all the types of carbohydrates combined: sugar, fibre and starch.
Sugar and fibre get a starring role on the nutrition label because we care about them. Starch is not shown, so to figure out how much starch a food contains, you need to calculate using the following formula:
Total starch (grams) = Total carbohydrate (g) – dietary fiber (g) – sugar (g)
In theory, net carbs are the number of carbs from food that can affect blood sugar levels. The thinking behind net carbs is that insoluble fibre and sugar alcohols (which are not digested by the body and do not enter the bloodstream) should not count toward the overall carbohydrate intake.
The concept of net carbs became popular with the emergence of keto and the Atkins Diet. To calculate net carbs, take the total grams of carbohydrates and subtract the grams of dietary fibre and sugar alcohols.
Net Carbs = total carbohydrate (g) – dietary fibre (g) – sugar alcohols (g)
It is important to note “net carbs” is not a scientifically defined term and is not regulated by the FDA on food packaging. Certain fibres and sugar alcohols, particularly the kinds that are added to processed foods to lower the net carb content, can be at least partially digested and affect blood sugar levels. This is why it is a good idea to prioritize whole foods in general, and when tracking net carbs.
Most countries outside the United States don’t count fibre or sugar alcohols toward their carbohydrate totals on food labels, as they are already tracking net carbs as their standard practice. If you are tracking net carbs to manage blood sugar, be sure to check with your doctor first.
When it comes to choosing carbohydrates to eat or drink, nutrient-dense sources are best. Here are three rules to help choose well. One caveat: If you are a highly athletic person who desires to optimize performance, not all of these carb rules apply.
Vegetables, beans, nuts and seeds, 100% whole-grain bread, pasta and brown rice should also be included in this rule. These foods are a source of fibre, vitamins, minerals and protein.
Foods like white rice, white bread and traditional pasta are more processed and have healthy nutrients — namely fibre — stripped from them.
Most sources of simple carbohydrates are considered “empty calories” because they are high in calories but contain little to no nutritional value. They are a likely culprit when it comes to spiking blood sugar. Fruit and milk are exceptions to this rule because they contain beneficial vitamins and minerals.
To perform basic functions, our bodies need carbs, particularly glucose since it is the preferred fuel for tissues and organs — and the only fuel for our red blood cells. Without enough carbohydrates, the body breaks down the hard-earned protein from muscles and organs to create usable glucose.
The Recommended Dietary Allowance (RDA) for carbohydrates is 130 grams per day. This is the minimum amount required to fuel an adult’s brain, red blood cells and central nervous system optimally. Without enough carbohydrates to maintain blood sugar in a normal range, the body starts breaking down protein — lean muscle tissue — into glucose to bring blood sugar back to normal.
The RDA of 130 grams of carbohydrates per day is a minimum for adult bodies to function properly. Most people need more. According to the Dietary Guidelines for Americans, carbohydrates should make up 45–65% of total calories in the diet. It is a large range because our bodies are all different and there’s no one-size-fit-all guidance for the absolute amount of carbs you should consume.
To determine carbohydrate needs in grams:
If you are not sure what percentage might be most appropriate, read more about how to optimize your macronutrient ranges, or follow this general rule of thumb:
To lose weight, start by keeping your carb intake to 45–50% of your calories. If you’re exercising vigorously for more than 1 hour per day or training for an endurance event like a marathon, aim for the 55–65% range.
A traditional “low-carb” diet has 40% or fewer calories coming from carbohydrates. There’s no denying that many have lost weight and kept it off successfully with this lifestyle. It’s popular for a reason, but it certainly is not the only way to lose weight — and it may not be for everyone.
Eating a low-carb diet (especially a restrictive one) affects your blood sugar levels, which can cause unfavourable side effects in some people, including being mild to downright uncomfortable, shakiness, nervousness or anxiety, chills, irritability, lightheadedness, headaches, hunger, nausea, fatigue, blurred vision, lack of coordination and more. These effects and the restriction required can make a low-carb diet difficult to follow.
If you choose to experiment with eating fewer carbs, here are seven tips to make the transition sustainable:
It may be tough to tell your reaction to low blood sugar since it varies from person to person. When starting a low-carb diet, look out for the signs and symptoms of low blood sugar (see above). If you experience them, eat a small serving of a carbohydrate-rich snack such as a piece of fruit, some crackers or a slice of bread.
Use an app to track your food for at least a week so you have a good understanding of how many grams of carbohydrates you consume daily. Then, slowly step down your carbohydrate intake goal by 5–10% (or about 30–50 grams daily) each week until you reach your desired goal. Remember to increase your fat and protein goals to offset the carbohydrates you’re reducing from your diet.
Tracking net carbs is most beneficial if you have decided that a low-carb diet is best for you, says registered dietitian Stepanie Nelson. “It allows for greater food flexibility and makes it easier to hit your fibre goal without going over your carb goal. Fibre is important for cardiovascular health, digestive health and feelings of fullness.” It’s also helpful to track net carbs “if you’re concerned about keeping your blood sugar levels in check since it can help you keep tabs on the foods that impact your blood sugar,” she notes.
Make those carbs count by choosing high-quality carbohydrates, like whole grains, fruits and vegetables, that are packed with fibre, vitamins and minerals. Choose high-quality proteins like eggs, legumes, chicken, tofu and lean cuts of beef and pork. Opt for healthy fats from foods that contain monounsaturated and polyunsaturated fats, such as fish, nuts, avocados and olive oil.
If you’re slashing carbs, you’ll most likely eat (and digest) more protein. For your body to break down and use protein optimally, it will need plenty of water. Check out the Hydration article for more information.
Be careful If you shed more than two pounds per week. You are likely losing more water weight and lean muscle than fat. Up your calories to lose weight at a slow but fat-busting pace.
Be honest with yourself: Are you happy eating a low-carb diet? Do you feel good? Our bodies can adapt to eating varying amounts of carbohydrates, but for some, the carbohydrate cravings and blood sugar side effects can be too difficult to bear. If you feel like your diet is too low in carbohydrates, don’t be afraid to add some back. Aggressively cutting carbs is not the only way to lose weight, and certainly is not right for everyone. Keep this in mind because you’re more likely to stick to your goals, lose weight and keep it off if you feel good and are happy with what goes into your body.