Understanding Carbohydrates as Fuel
First, a quick refresher. When you eat carbohydrates—whether from rice, rotis, potatoes, or fruit—your body breaks them down into glucose, which is your primary source of energy. This glucose can be used immediately for energy, or it can be stored in your muscles
and liver as glycogen. Think of glycogen as a fuel tank. Your body taps into these stores whenever it needs a quick energy boost, especially during physical activity. Insulin is the key hormone that manages this process, helping to move glucose from your bloodstream into your cells for use or storage.
The Active Body: A High-Demand Engine
For someone who is physically active, the story of carbohydrates is one of efficient use. During exercise, your muscles burn through their stored glycogen for fuel. After a workout, your muscles are like a dry sponge, ready to soak up glucose to replenish those depleted stores. This process is enhanced because regular exercise makes your muscles more sensitive to insulin. This means your body needs less insulin to do the job of moving glucose into the cells. For an active person, eating carbohydrates, especially after a workout, directs that energy primarily toward muscle recovery and refueling, not fat storage. Their 'fuel tanks' are regularly emptied and refilled.
The Sedentary Body: Full Tanks and Nowhere to Go
In contrast, a sedentary lifestyle tells a different story. If you spend most of your day sitting, your muscles aren't demanding much energy, which means your glycogen stores tend to stay full. When you eat carbohydrates, the resulting glucose enters the bloodstream, but the muscle 'fuel tanks' are already topped up. With nowhere to go, the excess glucose is more likely to be converted and stored as fat. Over time, a sedentary lifestyle combined with a diet high in carbohydrates can also lead to decreased insulin sensitivity, meaning the body has to work harder to manage blood sugar. This creates a metabolic environment that favors fat storage. Recent research highlights that sedentary individuals show significant decreases in mitochondrial function and fat oxidation capacity compared to active people.
What Do 'Two Servings' Actually Mean?
The headline's "two carb servings" is a useful example. A standard 'serving' of carbs is typically defined as 15 grams. So, two servings would be 30 grams. This could be about one medium-sized chapati, roughly a quarter cup of cooked rice, or a small baked potato. For an active person who just finished a workout, these 30 grams are quickly utilized to start the glycogen replenishment process. But for a sedentary person whose glycogen stores are already full, those same 30 grams represent surplus energy that the body may have to store as fat. It's the same food, but the context of the body receiving it changes everything.
Personalising Your Carb Intake
The takeaway isn't that carbs are 'bad' for sedentary people. It's that the amount and timing should be different. Instead of a one-size-fits-all approach, tailor your carbohydrate intake to your activity level. On days you're more active, your body can handle and will benefit from more carbohydrates to fuel performance and recovery. Recommendations for highly active individuals can range from 5 to 10 grams of carbs per kilogram of body weight per day. On days you're sedentary, it's wise to focus on a diet lower in carbohydrates and higher in protein and healthy fats, with carbs coming mainly from fibre-rich vegetables. Listening to your body and matching your fuel to the work required is the most sensible strategy.
