One cup of shredded romaine lettuce contains just 1 gram of total carbohydrates. After subtracting 0.6 grams of dietary fiber, the net carb count drops to roughly 0.4 grams per cup, making romaine one of the lowest-carb vegetables you can eat.
Carbs Per Serving Size
The carb count in romaine depends on how much you’re eating. A single cup of shredded pieces (the USDA standard measure) weighs about 47 grams and contains 1 gram of total carbohydrates. A larger salad-sized serving of about 70 grams bumps that up to 2.7 grams of carbs with 2.2 grams of fiber. Even if you eat an entire romaine heart, you’re unlikely to take in more than 4 or 5 grams of total carbohydrates.
The reason the numbers stay so low is simple: romaine lettuce is about 95% water by weight. That high water content means you get a lot of volume on your plate with very little caloric or carbohydrate payload. For anyone tracking carbs on a keto or low-carb diet, romaine is essentially a “free” food.
Net Carbs for Low-Carb Diets
Net carbs are what remain after you subtract fiber from total carbohydrates. Fiber passes through your digestive system without raising blood sugar, so many low-carb plans don’t count it. For one cup of shredded romaine, the math is straightforward: 1 gram total carbs minus 0.6 grams fiber equals 0.4 grams of net carbs. You could eat several cups as a salad base and still stay well under 2 grams of net carbs from the lettuce alone.
Romaine vs. Iceberg Lettuce
Iceberg and romaine are close in carb content. One cup of chopped iceberg has about 2 grams of total carbs and 1 gram of fiber. Cup for cup, the difference is negligible. Where romaine pulls ahead is in nutrient density: it delivers significantly more folate, vitamin A, and vitamin K than iceberg. It also contains more insoluble fiber, the type that helps move food through your digestive tract.
Fiber in Romaine
Romaine’s fiber is predominantly insoluble, with roughly 80% coming from cellulose. Insoluble fiber adds bulk to stool and supports regular digestion. Compared to crisphead (iceberg) varieties, romaine consistently contains more of this type of fiber. A 100-gram portion of fresh romaine can supply up to 10% of the daily recommended fiber intake for adults, which is a solid return for a food with almost no calories.
What Else Romaine Offers
Beyond its minimal carb footprint, romaine packs a surprising amount of nutrition for a leafy green that often gets overlooked in favor of kale or spinach. A single cup of raw romaine provides about 2,635 micrograms of lutein and zeaxanthin, two pigments that support eye health and protect against age-related vision changes. It’s also a good source of folate, delivering around 57 micrograms per 100 grams of fresh leaves.
Its high water content (90% to 100% range) also makes it a useful contributor to daily hydration, especially during warmer months or when you’re looking to add volume to meals without extra calories or carbs. Tossing a few cups of romaine into a wrap, taco, or grain bowl gives you crunch, hydration, and fiber for a fraction of a gram of net carbs.