Lettuce is one of the lowest-carb foods you can eat. A 100-gram serving of romaine contains just 1.2 grams of total carbohydrates, and iceberg comes in at roughly 3.4 grams per 100 grams. For context, most low-carb diets set a daily limit of 20 to 50 grams of carbs, so even a massive salad barely registers.
Carbs by Lettuce Variety
All lettuce varieties are low in carbs, but the numbers vary slightly depending on the type. Iceberg lettuce contains about 3.4 grams of carbs per 100 grams. Romaine is even lower at 1.2 grams per 100 grams. A single cup of shredded iceberg has roughly 2 grams of total carbs.
These numbers drop further when you calculate net carbs (total carbs minus fiber, which your body doesn’t absorb as sugar). Romaine lettuce has 2.1 grams of fiber per 100 grams, which actually exceeds its total carbohydrate count and brings net carbs to essentially zero. The practical takeaway: no matter which variety you grab, lettuce adds almost no digestible carbohydrate to your plate.
Why Lettuce Is Mostly Water
The reason lettuce is so low in carbs is simple: it’s almost entirely water. Butter leaf, green leaf, and spring mix varieties are about 96% water by weight. Iceberg sits at 95%, and romaine at 92%. That leaves very little room for carbohydrates, protein, or fat. A whole head of iceberg lettuce weighs around 700 to 800 grams, yet the total carb content for the entire head is only about 24 grams. You’d have to eat two or three full heads in a day to approach most people’s keto carb limits.
How Lettuce Fits a Keto or Low-Carb Diet
Strict keto dieters typically aim for 20 grams of carbs per day, while more moderate low-carb approaches allow up to 50 grams. Lettuce fits comfortably into either approach. Vegetables with more than 5 grams of carbs per 100 grams are generally considered starchy, and every lettuce variety falls well below that threshold.
Lettuce also has a low glycemic index, meaning it causes virtually no spike in blood sugar. This makes it useful not just for keto, but for anyone managing blood sugar levels. It works as a base for salads, a wrap substitute for tortillas or bread, or a crunchy addition to nearly any meal without meaningful carb impact.
Nutrients You Get Along With the Low Carbs
Lettuce may be light on calories and carbs, but the darker varieties pack a surprising nutritional punch. Romaine delivers 85% of your daily vitamin K and 48% of your daily vitamin A in a 100-gram serving, plus 34% of the daily value for folate. Red leaf lettuce is even higher in vitamin K at 117% of the daily value. Green leaf lettuce provides 105%.
Iceberg, by comparison, is the weakest performer. It offers just 3% of the daily value for vitamin A, 7% for folate, and 20% for vitamin K. If you’re choosing lettuce purely for its low-carb profile, any variety works. But if you want more nutrition per bite, romaine, red leaf, and green leaf varieties are significantly better choices. Butterhead (including Bibb and Boston types) falls in the middle, with 85% of the daily value for vitamin K and 18% each for vitamin A and folate.
Comparing Lettuce to Other Low-Carb Vegetables
Lettuce consistently ranks among the lowest-carb vegetables available. For comparison, spinach contains about 2.6 grams of carbs per 100 grams with 1.6 grams of fiber. Baby spinach is slightly lower at 2.4 grams. Both are excellent low-carb options, but romaine still edges them out.
- Romaine lettuce: 1.2 g carbs per 100 g
- Baby spinach: 2.4 g carbs per 100 g
- Mature spinach: 2.6 g carbs per 100 g
- Iceberg lettuce: 3.4 g carbs per 100 g
All of these fall well under the 5-gram threshold that separates low-carb vegetables from starchy ones like potatoes, corn, and peas. You can mix and match freely without worrying about carb counts adding up in any meaningful way.
Practical Portions and Real-World Numbers
Most people don’t weigh their lettuce, so it helps to think in terms of real servings. A cup of shredded iceberg contains about 2 grams of carbs. A large salad bowl with two or three cups of mixed lettuce might add 4 to 6 grams of total carbs before you factor in dressing, croutons, or other toppings. The lettuce itself is rarely what pushes a salad into higher carb territory.
If you’re using lettuce wraps instead of bread or tortillas, you’re swapping roughly 15 to 25 grams of carbs per wrap for less than 1 gram. Over the course of a week, that substitution alone can meaningfully reduce your total carb intake.