Net Carbs: What They Really Mean and Why They Matter

When you hear people talk about “net carbs,” especially in the fitness or low-carb community, it can sound confusing at first. Do you just subtract something from carbs? Are all carbs created equal? And is this really the key to fat loss or better energy? Let’s break it down simply.

What Are Net Carbs?

Net carbs are the carbohydrates that actually impact yourblood sugar and insulin levels.

They are calculated by taking total carbs in a food and subtracting fiber and sometimes sugar alcohols.

Formula:

Net Carbs = Total Carbs – Fiber – Sugar Alcohols (if applicable)

For example:

Food label shows 20g total carbs
10g fiber
5g sugar alcohols
Net carbs = 5g

This matters because fiber and most sugar alcohols aren’t digested the same way as other carbs, so they don’t cause the same blood sugar spike.

Why Do People Track Net Carbs?

Blood Sugar Control
If you’re managing insulin sensitivity, diabetes, or just want more stable energy, tracking net carbs helps you focus on the carbs that actually matter for blood sugar.
Low-Carb & Keto Dieting
Many keto or low-carb dieters use net carbs to stay under their daily carb limit without cutting out high-fiber foods like vegetables, nuts, and seeds.
Digestive Health
Fiber is essential for gut health, digestion, and satiety. Counting net carbs ensures you’re not avoiding fiber-rich foods unnecessarily.

The Fiber Factor

Not all carbs are equal, and fiber is the perfect example.

Soluble fiber slows digestion, helps control blood sugar, and promotes satiety.
Insoluble fiber adds bulk to stool and improves bowel movements.

Neither is broken down into glucose the way starches and sugars are, which is why they’re subtracted from the net carb count.

What About Sugar Alcohols?

Sugar alcohols (like erythritol, xylitol, and maltitol) are often used in “low-carb” or “keto” products. Some are digested partially, and some barely at all.

Erythritol: Almost zero impact on blood sugar → usually fully subtracted.
Xylitol: Partially absorbed, may slightly raise blood sugar.
Maltitol: Acts more like a regular carb, can spike blood sugar in many people.

This is why not all “low net carb” products are as blood-sugar friendly as they seem.

The Downsides of Focusing on Net Carbs

While net carbs can be useful, they’re not perfect:

Food marketing loopholes: Many “keto” snacks advertise low net carbs but use sugar alcohols that still spike blood sugar or cause digestive distress.
Ignoring calories: Even if fiber and sugar alcohols don’t fully count toward net carbs, they still contribute calories. Eating too many “low net carb” treats can stall fat loss.
Individual response matters: Some people tolerate sugar alcohols well, others get bloating, gas, or spikes in blood sugar depending on the type.

Practical Takeaways

Use net carbs to guide smart choices, especially if you’re on keto or want stable energy.
Prioritize whole food sources of carbs (vegetables, fruits, beans, oats) rather than processed “low net carb” bars.
Pay attention to how you feel. Labels don’t always tell the full story—your blood sugar response and digestion matter more than marketing.

Bottom Line

Net carbs are a helpful way to understand how carbs affect your body, especially if you’re watching blood sugar or following a low-carb diet. But don’t let labels trick you—fiber-rich whole foods should be your foundation, not just low-carb snack products.

If you track net carbs, do it as a tool, not a shortcut. Combine it with quality nutrition, consistent training, and smart calorie balance, and you’ll see results that actually last.

Tommy's Take by Tommy Pomatico 8/18