Many of us have heard someone say that they cut out carbohydrates and lost weight, implying that carbohydrates cause undesirable weight gain. However, carbohydrates are an essential nutrient, and eliminating them from your diet can result in severe health consequences.
Functions of Carbohydrates
Carbohydrates are your body’s primary source of energy. Glucose is the preferred energy source for your central nervous system and the only energy source for your red blood cells. Stored glucose, known as glycogen, is present in the liver and muscles to provide energy, preserve muscle, and regulate blood glucose in a period of fasting. Carbohydrates are vital in producing serotonin and dopamine, two neurotransmitters associated with mood regulation, brain function, appetite, muscle movement, and sleep. Fat metabolism and protein synthesis are also inhibited when carbohydrate intake is inadequate. Fiber, a non-digestible carbohydrate found in fruits, vegetables, legumes, and whole grains, aids in digestion and helps regulate blood sugar. It may help reduce cholesterol as well.
Sources of Carbohydrates
Carbohydrates can be found in desserts, grains, vegetables, fruits, dairy, and legumes. They take the form of sugars, fibers, and starches. Examples of these foods include:
· Desserts/Sweets: pie, cake, cookies, soda, candy
· Grains: oatmeal, pasta, rice, bread, cereal, crackers
· Vegetables: carrots, beets, celery, tomatoes, onions, broccoli, etc.
o Starchy vegetables: potatoes, corn, peas
· Fruits: bananas, apples, oranges, watermelon, peaches, grapes, mangoes, etc.
· Dairy: milk, yogurt, ice cream
· Legumes: beans, lentils
Simple carbohydrates are quickly digested by the body, as they are smaller molecules that can readily be broken down and absorbed. These foods include desserts, soda, candy, syrup, dairy, and fruit juice concentrate. Fruit contains simple sugars as well, but they also contain complex carbohydrates in the form of fiber. Complex carbohydrates, such as starches and fibers, are much larger molecules and take longer to digest and absorb (or may not be digested at all in fiber’s case). These carbohydrates are released into the blood stream at a much slower rate and generally do not cause blood sugar to rise and fall rapidly. These foods include grains, vegetables, and legumes. Fruit can actually contain both complex and simple carbohydrates.
Both simple and complex carbohydrates are useful and can fit into an individual’s diet. However, simple sugars should be consumed in smaller amounts compared to complex carbohydrates in order to control blood sugar and satiety.
How Many Grams of Carbohydrates Do I Need?
Generally speaking, carbohydrates should make up 45-65% of your total calories each day. This may differ depending on activity level, type of activity, and even medical conditions. For the average adult, I like to start at 50%.
Based on a 1600 calorie diet, one would need ~200 g of carbohydrates in order for this to make up 50% of the calories. Below, I will walk through how to calculate this. Note that carbohydrates contain 4 calories/gram.
1600 calories * 50% = 1600 * 0.5 = 800 calories
800 calories / 4 calories/gram = 200 grams
*To calculate how many carbohydrate exchanges this would be, divide your final answer by 15 g/1 exchange. The example above would equal 13-14 carbohydrate exchanges per day.
Carbohydrate Cutting and “Weight” Loss: The Science Explained
Many celebrities and health coaches claim that cutting out carbohydrates helped them lose weight. Although the number on the scale may have decreased, it is likely that very little fat mass was actually lost. Our body prefers to use glucose as its main energy source, and when we exclude it, our body is forced to use up glycogen, which is the body’s stored glucose. Glycogen is a large molecule that is stored with water, so once it is broken down and used, the water is lost as well, resulting in a lower weight. Once carbohydrates are added back into the diet, glycogen stores are replenished as well as water, resulting in weight gain.
When speaking about weight loss for improving health, it is important to know that this is referring to fat loss rather than just weight loss. With this being said, true fat loss comes from a calorie deficit. In simpler terms, this means consuming fewer calories than your body uses.
By managing portion sizes, you will be able to create a calorie deficit while still providing your body with the nutrients it needs for vital functions.