Ever since the introduction of carb-cutting diets some 20 years ago, carbohydrates have been a source of nutritional controversy, particularly among those trying to lose weight. The science to support low-carb diets has been conflicting at best—but this isn’t surprising since we all know that nutrition needs are highly individual, particularly where weight loss is concerned.
Because individual carbohydrate needs aren’t one-size-fits-all, we’ve put together an informational guide to help you personally optimize your carbohydrate consumption and choose healthier carb options—whether you’re trying to lose weight or train for your first half-marathon (or anything in between).
Carbohydrates are found in almost all foods, and they provide 4 calories for every gram. As you can imagine, not all carbohydrates are created equal. Different types of carbohydrates will affect your body (and blood sugar) differently.
Carbohydrate-containing foods generally have a combination of two types of carbohydrates: simple and complex.
They’re also known as “sugar.” This carbohydrate is made of one sugar or two sugar building blocks connected in a chain. The building blocks can be glucose, fructose and galactose. Because the chains are short, they’re easy to break down, which is why they taste sweet when they hit your tongue. Foods high in simple carbohydrates include sweeteners (table sugar, syrup, honey), candies, jellies and jams, fruits, beans and refined flour.
Complex carbs can be either “starch” or “fiber.” This carbohydrate is made of three or more sugars connected in a chain. 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. Foods high in complex carbohydrates include bread, rice, pasta, beans, whole grains and vegetables.
For even more on carbohydrates, check out this Nutrition 101 post.
Just looking at a nutrition label, you’ll see “dietary fiber” and “sugar” listed under “total carbohydrates,” but do you ever wonder why the grams never add up? “Total carbohydrate” includes all the types of carbohydrates: sugar, fiber and starch. Sugar and fiber get a starring role on the nutrition label because we care about them. However, starch doesn’t, so if you want to figure out how much starch a food contains, you have to do some math. Here’s the formula in case you’re interested:
total starch (grams) = total carbohydrate (g) – dietary fiber (g) – sugar (g)
Carbohydrates are essential to life, and they’re found in almost all foods. To perform basic functions, our bodies need carbs, particularly glucose since it’s the preferred fuel for tissues and organs. In fact, glucose is the only source of fuel for our red blood cells. Without enough carbohydrates, the body will break down hard-earned protein from muscles and organs to create usable glucose for these tissues and organs.
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. What happens when you eat too few carbs? Without enough carbohydrates to maintain your blood sugar in a happy range, the body starts breaking down protein (which it can turn into glucose) to bring blood sugar back to normal. This is terrible news—you lose some of your lean muscle during this process!
Of course we’re expected to eat more than the RDA of 130 grams carbohydrates per day: According to the Dietary Guidelines for Americans, carbohydrates should make up 45 to 65% of total calories in our diet—this is a good range for the average person. But, our bodies are adaptable so there’s no one-size-fit-all guidance for the absolute amount of carbs you should consume.
The 45-65% carbohydrate range is such a big one, and it may be difficult to pinpoint the right percentage. If you do not manually adjust your macronutrient goals, MyFitnessPal allots 50% of your calories to carbohydrates, but we encourage you to change these goals based on what your personal needs are. If you’re 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 determine your carbohydrate needs in grams:
- Step 1: Decide what percentage of carbohydrates you need. Choose a 45%, 50%, 60% or 65% carbohydrate diet. Convert this number to a decimal (for example, 50% is 0.5).
- Step 2: Multiply your “Total Calorie Goal” by the decimal value. This gives you the number of calories from carbohydrates.
- Step 3: Take the number of calories from carbohydrates and divide by 4 to get the grams of carbohydrate.
Does this match your carbohydrate goal in the app?
Eating a higher-carbohydrate diet is beneficial to performance for daily exercise in moderate to vigorous aerobic activity (think running, swimming, biking). Why? Because the more carbs you eat, the more glucose you allow your body to store in the form of muscle glycogen. The more glycogen you store, the more fuel you have available for your next bout of exercise.
For optimal athletic performance, it’s the absolute amount of carbohydrate (in grams) you eat that matters, not the percentage of total calories that comes from carbs. If it’s something you’re interested in, use this general guideline to calculate the recommended grams of carbs you should eat daily to enhance athletic performance. Use these calculations to change your carbohydrate goal in the MyFitnessPal app.
|Type of Activity||Recommended Carbohydrate|
|Very light training program||3-5 grams/kg|
|Moderate-intensity training programs, 60 min/day||5-7 grams/kg|
|Moderate- to high-intensity endurance exercise, 1-3 hours/day||6-10 grams/kg|
|Moderate- to high-intensity exercise, 4-5 hours/day||8-12 grams/kg|
Source: C.A. Rosenbloom, E.J. Coleman (Eds.) Sports Nutrition A Practice Manual for Professionals. 5th edition. Academy of Nutrition and Dietetics, Chicago, IL; 2012.
If you’re a runner, you can learn more about “carbohydrate loading” and how to adjust carbohydrate goals for running.
A traditional “low-carb” diet has 40% or less calories coming from carbohydrates, and 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 adversely affect how you feel. It may also be tough to maintain over time. Carbohydrate cravings are common at the beginning of a low-carb diet because your blood sugar may dip lower than the level your body is accustomed. You can experience unfavorable side effects as your body adjusts to this new state. The low down on low blood sugar: we all experience it differently and to different degrees. The signs and symptoms are general enough that they could be caused by issues other than low blood sugar. They range from being mildly to downright uncomfortable and include shakiness, nervousness or anxiety, chills, irritability, lightheadedness, headaches, hunger, nausea, fatigue, blurred vision, lack of coordination and more. Depending on your individual reaction to eating low carb, you may have none to many of the signs and symptoms described.If you choose to experiment with a lower-carb lifestyle, here are six tips to make the transition both more manageable and sustainable:
1. DEAL WITH BLOOD SUGAR LOWS
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, be on the lookout 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.
2. EASE INTO A LOWER-CARB LIFESTYLE USING THE MYFITNESSPAL APP AS A TOOL
Use the 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 in order to offset the carbohydrates you’re reducing from your diet.
3. CHOOSE BALANCED, NUTRIENT-DENS FOODS
Make those carbs count by choosing high-quality carbohydrate foods—like whole grains, fruits and vegetables—that are packed with fiber, 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.
4. STAY HYDRATED BY DRINKING MORE FLUIDS
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’s going to need plenty of water. To help you stay hydrated, here are 25 life hacks for drinking more water.
5. BE WARY OF RAPID WEIGHT LOSS
If you shed more than 2 pounds per week on your diet, be careful. You’re likely losing more water weight and lean muscle than fat. Up your calories to lose weight at a slow but fat-busting pace.
6, GAUGE YOUR HAPPINESS, AND KNOW WHEN TO ADD BACK THE BREAD
Be honest with yourself: Are you happy eating low-carb foods? 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 constant struggles. If you feel like your diet is a little too low in carbohydrates, don’t be afraid to add some back. Aggressively cutting carbs isn’t the only way to lose weight, and certainly isn’t 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.
Whether you’re a healthy individual looking to lose or maintain weight, or optimize athletic performance, here are three rules of thumb to help you choose healthy carbohydrate foods. One caveat: If you’re a highly athletic person whose desire is to optimize performance, not all of these carb rules will apply to you. Read this instead.
1. CHOOSE WHOLE FOOD SOURCES OF COMPLEX CARBS
Vegetables, beans, nuts and seeds, one-hundred percent whole-grain breads, pasta and brown rice should also be included in this rule. These foods are a source of fiber, vitamins, minerals and protein.
2. EAT LESS COMPLEX CARBS FROM REFINED SOURCES
Foods like white rice, white bread and traditional pasta are more processed, and have healthy nutrients stripped from them—namely fiber.
3. ENJOY SIMPLE CARBOHYDRATES IN MODERATION
Most sources of simple carbohydrates are considered “empty calories” because they’re high in calories but contain low to no micronutrients. They’re a likely culprit when it comes to spiking blood sugar. You can consider fruit and milk an exception to this rule because both contain beneficial vitamins and minerals.