Green leafy choy is a low-fat staple in many diets, but the fat content you actually eat depends heavily on how it is prepared. Raw bok choy, choy sum, and gai lan usually contain less than 0.5 g of total fat per 100 g, while the same greens stir-fried in oil can climb to 3–7 g per 100 g. This calculator converts your real serving weight and the fat in that serving into a clean per-100g figure, so you can compare dishes, track macros, and log meals more consistently.
Enter the weight of choy you ate, the total fat in that serving from a food label, tracking app, or your own recipe estimate, and optionally the calories. The tool then shows fat per 100 g, calories from fat, the share of calories from fat, and how much of a 78 g daily value the serving uses. Quick-fill buttons provide typical values for steamed bok choy, raw choy sum, and stir-fried preparations.
This tool is useful for anyone counting fat macros, planning low-fat vegetable meals, or trying to understand why a “simple vegetable dish” sometimes contains more fat than expected.
🥬 Choy Fat per 100g Calculator
Convert fat from any choy serving to a standard 100 g reference, plus fat calories and daily value.
Quick Start: From Serving to Standard 100 g
Start by weighing the cooked choy portion you actually ate. A kitchen scale is most reliable because leafy greens shrink dramatically when cooked — 200 g of raw bok choy can become roughly 120–150 g after wilting.
Find the total fat in that exact serving from a recipe, packaged label, or tracking app. For a restaurant dish, estimate the added oil: 1 teaspoon of vegetable oil adds about 4.5 g of fat, and 1 tablespoon adds about 14 g. Enter that fat amount, optionally add the serving’s calories if you want the fat calorie percentage, then press Calculate. The quick-fill buttons give typical references for steamed bok choy, raw choy sum, a light stir-fry, and a restaurant-style stir-fry.
Formula Explained
The core conversion is simple:
Fat per 100 g = (total fat in serving ÷ serving weight in grams) × 100
The tool also applies two common nutrition conversions: calories from fat = fat grams × 9 kcal/g, and fat calorie percentage = (calories from fat ÷ total calories) × 100. Daily value is calculated as fat grams ÷ 78 g × 100, using the FDA reference daily value for total fat on a 2,000-calorie diet.
Fat in Choy by Cooking Method
Choy varieties are naturally low in fat, but preparation changes things dramatically. Typical totals, including cooking oil where relevant, are:
| Preparation | Typical fat (g per 100 g) |
|---|---|
| Raw bok choy or napa cabbage | 0.2 |
| Steamed or boiled choy, no added oil | 0.2–0.4 |
| Raw choy sum or gai lan | 0.4 |
| Stir-fried with about 1 tsp oil per 200 g greens | 2.5–4 |
| Oil-heavy restaurant stir-fry | 5–8 |
Exact fat depends on how much oil is absorbed and how much sauce is added. For a similar per-100g comparison in another dish, see the curry fat per 100g calculator.
Worked Examples
Example A — steamed bok choy: You eat 200 g of steamed bok choy containing 0.4 g total fat.
Fat per 100 g = (0.4 ÷ 200) × 100 = 0.2 g. Calories from fat = 0.4 × 9 = 3.6 kcal, which is about 0.5% of a 78 g daily value.
Example B — restaurant stir-fry: A 150 g portion contains 6 g fat and 140 kcal total.
Fat per 100 g = (6 ÷ 150) × 100 = 4.0 g. Calories from fat = 54 kcal, so fat provides 54 ÷ 140 × 100 ≈ 39% of the dish’s calories. Daily value ≈ 7.7%.
These examples show why two bowls of “choy” can look similar but differ enormously in fat — cooking oil is doing the heavy lifting.
Common Mistakes to Avoid
- Mixing raw and cooked weights. Use cooked weight in the serving field; water loss changes the per-100g result.
- Forgetting cooking oil. Choy itself is nearly fat-free, but pan oil usually makes up most of the fat total.
- Using saturated fat instead of total fat. The calculator expects total fat; saturated fat is only a subset.
- Trusting a generic app entry. Database values for stir-fried greens vary widely by recipe and preparation.
- Omitting the calorie field when you want a fat percentage. Without calories, the share of fat energy cannot be calculated.
Tip: Keep a note of how much oil you add to a stir-fry. One teaspoon is about 4.5 g of fat, and one tablespoon is about 14 g. Add that to the greens’ natural fat for a reliable recipe total.
Frequently Asked Questions
Is choy naturally high in fat? No. Plain leafy choy typically has 0.2–0.4 g fat per 100 g, placing it among the lowest-fat vegetables. Most fat in choy dishes comes from cooking oil, sauces, or animal ingredients.
How do I estimate fat when there is no label? Start from the raw or steamed baseline, then add oil: 1 teaspoon ≈ 4.5 g fat, 1 tablespoon ≈ 14 g. Divide the total recipe fat by the cooked weight and multiply by 100.
Does this work for other greens? Yes. The per-100g conversion is universal. Just enter the serving weight and the fat in that serving. For a fatty-food comparison, the salmon fat calculator is more relevant than a vegetable calculator.
Why does my app show 2 g fat per 100 g for a similar dish? The database entry may include a standard amount of added oil, or it may be based on a specific restaurant recipe. This calculator lets you override that with your exact serving data.
For authoritative raw-vegetable nutrient data, see USDA FoodData Central.