Balancing Your Macros: Carbohydrates

Think carbs cause weight gain? Learn why carbohydrates are your body’s main fuel, how much you really need, the difference between simple vs complex carbs, and how excess can affect blood sugar and health.

Lots of people today are afraid of carbs. Whenever someone notices belly fat or gains weight, the first suspect is often carbohydrates. They’ll blame their rice, bread, or sugar—but rarely do they think about their physical activity levels or total calorie intake. So, are carbs really the problem? Or are they just convenient scapegoats? Let’s find out.

Why Do We Need Carbohydrates?

Carbohydrates are your body’s primary fuel source. They break down into glucose, which powers every cell from your brain, to muscles, to your organs. Without enough carbs, your energy drops, training suffers, mood swings appear, and even normal day-to-day functioning can be harder. So yes, don’t be afraid of them, they’re crucial.

How Much Carbs Should You Eat?

Here are some general guidelines, though as with all macros they’ll depend on your activity level, age, metabolism, and goals:

For healthy, moderately active adults: about 5-7 grams of carbs per kilogram (g/kg) of body weight per day is a common recommendation.
If you’re very active (long endurance exercise, high daily training load), you may need more—sometimes 7-10 g/kg, even up to 10-12 g/kg in those extreme endurance cases.
As a percentage of your daily calories, carbs should usually make up about 45-65% of total calorie intake for most healthy people.

What Happens If You Eat Too Little or Too Much Carbs?

Carbs are required but like everything else, balance is key.

Too few carbohydrates: Your body may switch to burning fat, and enter ketosis, which for some shows up as “keto flu” with fatigue, headaches, dizziness. Additionally, low fiber intake (because carb sources often bring fiber) can cause digestive issues like constipation. Energy levels suffer, workouts feel harder. Over long term, insufficient carbs may lead to micronutrient deficiencies and impact mood, immune function, etc.

Too many carbohydrates: When you eat more carbs than needed, the excess glucose can first fill your glycogen stores (in liver & muscles). When those are full, extra gets converted to fat (a process called de novo lipogenesis). Over time this can lead to weight gain and obesity. Excessive glucose signals the pancreas to produce more insulin, which eventually causes cells to become less responsive to its signals. This creates a "vicious cycle" where more and more insulin is needed to maintain normal blood sugar levels, eventually leading to insulin resistance, pre-diabetes, and potentially type 2 diabetes.

What Should Be the Source of Carbohydrates?

Not all carbs are created equal. What you choose matters a lot.

Simple vs Complex Carbohydrates:
Simple carbs (sugars) are digested quickly, tend to spike blood sugar. Sugars are simple carbohydrates. Sugars can be naturally occurring or refined. It’s best to prioritize naturally occurring sources such as honey, milk, and fresh or dried fruits, since they come with beneficial micronutrients. In contrast, refined sugar lacks a meaningful nutrient profile and mostly contributes empty calories.
Complex carbs take longer to break down; they usually come with more fiber, vitamins, minerals, and give a more gradual energy release. Starch and fibers are complex carbohydrates .Fiber is a complex healthy carbohydrate with two types — soluble and insoluble. Soluble fiber dissolves in water to form a gel, slowing digestion, regulating blood sugar and nourishing gut bacteria. Insoluble fiber does not dissolve in water, adds bulk to stool, and helps food pass more quickly through the digestive system, preventing constipation. Starches are complex carbohydrates that also give your body vitamins and minerals (micronutrients). It takes your body longer to break down complex carbohydrates. As a result, blood sugar levels remain stable, and fullness lasts longer. Fruits, vegetables and whole grain products are sources of complex carbs.

Conclusion

Carbohydrates are essential—your body’s primary fuel—so blaming them completely for weight gain isn’t fair. What matters more is how much you eat, what type of carbs you choose, and how active you are.

For most people, somewhere in the range of 5-7 g/kg carbohydrate intake works well, and more if you have high physical activity. Keep carbs between 45-65% of total calories for balanced energy and health.

Choose complex carbs, high-fiber foods, whole grains, fruits & vegetables. Limit refined sugars and ultra-processed carbs to avoid blood sugar spikes, weight gain, and metabolic issues.

Balancing macros is about making smart choices, not eliminating anything.

Balancing Your Macros: Carbohydrates — How Much, What Types & Why They Matter