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Low-Carb Vegetables: Net Carbs per Serving From USDA Data

A low-carb vegetables list with total carbs, fibre and net carbs per serving and per 100 g, worked out from USDA SR Legacy data, from spinach to onions.

By Published 4 min read

Reign Creative LLC makes Ketora: Keto Diet Carb Tracker, which this article links to, so we have a commercial interest in it. How we write and check articles.

AI-assisted article. Drafted with AI tools from the sources cited below and checked by automated tests and an AI editorial review. No person has reviewed it yet. How we write and check articles.

Key takeaways

  • Leafy greens are the lowest: a cup of raw spinach has about 0.4 g of net carbs and a cup of shredded romaine about 0.6 g, from USDA data.
  • Every vegetable in this list's middle table, including cauliflower, broccoli, zucchini and green bell pepper, stays under 5 g of net carbs per serving.
  • Onions and carrots are higher: about 12.2 g and 8.7 g of net carbs per chopped cup.
  • Net carbs here are total carbohydrate minus dietary fibre; the US Nutrition Facts label lists both but has no net carbs line.
  • Compare per 100 g as well as per serving, because a cup of kale weighs 21 g and a cup of broccoli 91 g.

Vegetables are not all equal in carbohydrate. This list gives total carbohydrate, fibre and net carbs for common vegetables, per typical serving and per 100 g, worked out from the US Department of Agriculture's SR Legacy data in FoodData Central.

How net carbs are counted here

Net carbs, as this list counts them, are total carbohydrate minus dietary fibre. The FDA's Nutrition Facts label lists Total Carbohydrate and Dietary Fiber as separate lines, but it has no "net carbs" line, so the subtraction is yours to do. Net carbs explained covers the definition and its caveats, including sugar alcohols, which these whole vegetables do not contain.

All values are for raw vegetables, using the SR Legacy entries (for example "Broccoli, raw" and "Lettuce, cos or romaine, raw") and the portion weights USDA lists; each table gives both the per-serving and the per-100 g figure. Cooked vegetables have their own SR Legacy entries with different values per cup, so look those up if you weigh food after cooking.

The lowest: leafy greens and watery vegetables

Vegetable Serving Total carbs Fibre Net carbs Net per 100 g
Kale 1 cup (21 g) 0.9 g 0.9 g 0.1 g 0.3 g
Spinach 1 cup (30 g) 1.1 g 0.7 g 0.4 g 1.4 g
Romaine lettuce 1 cup shredded (47 g) 1.5 g 1.0 g 0.6 g 1.2 g
Celery 1 cup chopped (101 g) 3.0 g 1.6 g 1.4 g 1.4 g
Cucumber, with peel ½ cup slices (52 g) 1.9 g 0.3 g 1.6 g 3.1 g
Mushrooms, white 1 cup slices (70 g) 2.3 g 0.7 g 1.6 g 2.3 g

Most non-starchy vegetables: under 5 g a serving

Vegetable Serving Total carbs Fibre Net carbs Net per 100 g
Asparagus 1 cup (134 g) 5.2 g 2.8 g 2.4 g 1.8 g
Eggplant 1 cup cubes (82 g) 4.8 g 2.5 g 2.4 g 2.9 g
Zucchini 1 cup chopped (124 g) 3.9 g 1.2 g 2.6 g 2.1 g
Cabbage 1 cup chopped (89 g) 5.2 g 2.2 g 2.9 g 3.3 g
Cauliflower 1 cup chopped (107 g) 5.3 g 2.1 g 3.2 g 3.0 g
Tomato 1 medium (123 g) 4.8 g 1.5 g 3.3 g 2.7 g
Broccoli 1 cup chopped (91 g) 6.0 g 2.4 g 3.7 g 4.0 g
Green beans 1 cup (100 g) 7.0 g 2.7 g 4.3 g 4.3 g
Green bell pepper 1 cup chopped (149 g) 6.9 g 2.5 g 4.4 g 2.9 g
Brussels sprouts 1 cup (88 g) 7.9 g 3.3 g 4.5 g 5.1 g

Higher per cup: red pepper, carrot and onion

Vegetable Serving Total carbs Fibre Net carbs Net per 100 g
Red bell pepper 1 cup chopped (149 g) 9.0 g 3.1 g 5.9 g 3.9 g
Carrots 1 cup chopped (128 g) 12.3 g 3.6 g 8.7 g 6.8 g
Onion 1 cup chopped (160 g) 14.9 g 2.7 g 12.2 g 7.6 g

Avocado, botanically a fruit but eaten like a vegetable, is unusual: half an avocado, about 100 g, has 8.6 g of carbohydrate but 6.7 g of fibre, leaving about 1.8 g net, though it is high in fat and calories.

Why both columns matter

Servings hide weight. A cup of raw kale weighs 21 g and a cup of chopped broccoli 91 g, so kale looks far lower per cup. Per 100 g, kale (0.3 g) is still lowest, but broccoli (4.0 g) and Brussels sprouts (5.1 g) are closer to green beans (4.3 g) than the cups suggest. Red and green bell peppers show the other effect: the same 149 g cup, but the red pepper carries more sugar (4.2 g against 2.4 g per 100 g) and about 1.5 g more net carbs.

A worked example: a low-carb dinner plate

A plate of a cup of cauliflower (3.2 g), a cup of broccoli (3.7 g) and a cup of shredded romaine (0.6 g) comes to about 7.5 g of net carbs (7.4 g before rounding). Swap the cauliflower for a cup of chopped carrot (8.7 g) and the plate rises to about 13 g (12.9 g before rounding). Against a low daily limit, such as the 20 g or 50 g examples on the Ketora app page (examples, not recommendations; any limit of your own is best set with a health professional), that one swap moves a meaningful share of the day. Keto macros explained covers how targets are set, and low-carb fruits gives the same figures for fruit.

Tracking it

Ketora: Keto Diet Carb Tracker, one of our health and nutrition apps, works out net carbs as you log, taking fibre and sugar alcohols away from total carbohydrate, and shows net and total carbs side by side. Values from your own scale and food labels will be closer to what you actually eat than any reference table.

Good to know

Frequently asked questions

Which vegetables are lowest in carbs?
Leafy greens. USDA data give about 0.4 g of net carbs in a cup of raw spinach, 0.6 g in a cup of shredded romaine and 0.1 g in a cup of raw kale, because those cups weigh little and carry much of their carbohydrate as fibre.
How many net carbs are in broccoli?
About 3.7 g in a cup of chopped raw broccoli (91 g): roughly 6.0 g of total carbohydrate minus 2.4 g of fibre, according to USDA SR Legacy data.
Are onions and carrots low-carb vegetables?
They are the highest in this list. A chopped cup of raw onion has about 12.2 g of net carbs and a chopped cup of raw carrot about 8.7 g, though smaller amounts used for flavour add much less.
Is avocado low in net carbs?
Yes. Half an avocado (about 100 g) has about 8.6 g of total carbohydrate but 6.7 g of fibre, leaving about 1.8 g of net carbs, though it is high in fat and calories.

Sources

  1. FoodData Central: SR Legacy (April 2018 release) (opens in a new tab)US Department of Agriculture, Agricultural Research Service — accessed
  2. How to Understand and Use the Nutrition Facts Label (opens in a new tab)US Food and Drug Administration — accessed

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