Where our numbers come from
Every calorie Blobb shows you comes from a published source or from a figure we worked out from one. This page lists all of them. Where we had to estimate, it says so.
All of these are estimates. Foods vary by batch, brand and how they were cooked, and the studies below report ranges, not single values. None of this is medical or nutritional advice. See section 5 of the Terms.
Food data
Calories and nutrients for single foods come from the USDA's FoodData Central. We use four of its datasets, copied into our own database:
- Foundation Foods: the USDA's most recent lab analyses of basic foods. Many of these list energy only as an Atwater value, so we use the food-specific Atwater energy, and the general Atwater energy if that's missing too. The few Foundation foods with no energy value at all are left out of search, so they can't quietly log as 0 kcal.
- SR Legacy: the USDA's long-standing reference database. Most of our everyday foods and their household measures (cups, tablespoons, pieces) come from here.
- Survey Foods (FNDDS): foods and dishes as people report eating them in the U.S. national diet survey, including many mixed dishes.
- Branded Foods: nutrition labels that manufacturers send to the USDA.
Restaurant items come from the nutrition information chains publish for their menus, collected mostly through a third-party aggregator. We can't check those figures against the food itself.
Your calorie target
Your daily target comes from published energy equations: Mifflin-St Jeor for adults, the Institute of Medicine equations for ages 9–18, and Schofield for the under-18 floor. How we use them, and where we made our own judgement calls, is on the Method page.
Frying oil
A recipe that says "3 cups oil for frying" doesn't mean you eat 3 cups of oil. Most of it stays in the pot. So Blobb counts only the oil the food keeps, as a share of the food's raw weight, which depends on how the food was coated or cut.
Japanese dietitians call this the oil absorption rate, 吸油率. Our main sources are a standard Japanese cooking reference (Basic Data below), Japanese hospital and city health office handouts, and a German table of cooking losses used for European food composition work (Bognár). Where they disagree, we use a figure near the middle.
| How it was fried | Oil kept | What the sources say |
|---|---|---|
| Fatty or skin-on cuts, unbreaded (pork belly) | 0% | These lose fat into the oil instead (Bognár; Nutrition Research and Practice 2025) |
| Thick starchy pieces (fries, plantain) | 5% | Bognár 5% for French fries; Basic Data 2–4% for potato wedges and sticks |
| Unbreaded meat, fish, tofu | 5% | Basic Data 5% for plain-fried chicken; Bognár 0–1% for meat and fish |
| Dusted in starch or flour (karaage) | 8% | Basic Data 8%; Kyotango 6–8%; TMD 5–7% |
| Pan-fried fish, unbreaded | 8% | Kalogeropoulos et al. 4.5–14.2%, lower for fattier fish |
| Unbreaded vegetables | 10% | TMD: shishito about 10%, eggplant about 14%, mushrooms about 20% |
| Breaded (panko, breadcrumbs) | 12% | Japanese sources mostly 10–20%; Bognár lower, 4–6% |
| Wrapped (spring rolls, gyoza) | 12% | Two dietitian sources give 10–12%. We found no lab data, so treat this as an estimate. |
| Thin starchy slices (chips) | 13% | Basic Data 15% for 1.5 mm potato slices; about 11% from USDA's potato and chip compositions |
| Wet-battered (tempura) | 15% | Basic Data 15%; hospital and city handouts 15–25% |
If you sauté, stir-fry, stew or braise, the oil stays in the dish, so Blobb counts all of it.
When you convert a recipe, Blobb guesses how it was fried from the ingredients, such as panko or a starch coating. You can change the frying style and which ingredients were fried in the template editor.
Changed 17 October 2026. When we checked every rate against these sources, three were off. Breaded went from 20% to 12% and chips from 30% to 13%. Unbreaded frying, which was 7% for everything, became 5% for meat, fish and tofu and 10% for vegetables, because watery vegetables keep far more oil than lean meat does.
Marinades and brines
A marinade you pour off isn't eaten. Only what the food soaks up is, so that's all Blobb counts.
| Situation | Counted | What the sources say |
|---|---|---|
| Marinade drained off, meat grilled or fried | 5% of the meat's weight | Measured uptake of 3–6% (Tkacz et al. 2021; Fencioglu et al. 2022; Rahman et al. 2023) |
| Same, thin slices (bulgogi, tapa, yakiniku) | 8% | No direct measurement found. Thin slices have more surface per gram, so we set this higher. It's an estimate. |
| Marinade cooked down or used as the sauce | All of it | Nothing is thrown away |
For pickles, we assume the salt, sugar and vinegar even out between the vegetable's water and the brine, and count the vegetable's share. That's a diffusion model, not a measured rate. We found no published figure to check it against, so it's an estimate.
Full references
Food data
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Foundation Foods, SR Legacy, Survey Foods (FNDDS) and Branded Foods.
Calorie target
Listed on the Method page.
Frying oil
- Bognár: Bognár A. Tables on weight yield of food and retention factors of food constituents for the calculation of nutrient composition of cooked foods (dishes). BFE-R-02-03, Federal Research Centre for Nutrition, Karlsruhe, 2002.
- Basic Data: 女子栄養大学出版部『調理のためのベーシックデータ 第5版』, as quoted by おいしい健康 and Wikipedia (吸油率).
- Kyotango: Kyotango City health office, 揚げ物の種類によって違う吸油量.
- TMD: Tokyo Medical and Dental University Hospital, clinical nutrition department, recipe sheet 031.
- くみたす, citing 日本栄養改善学会『食事調査マニュアル』改訂2版 (2008) and the 日本食品標準成分表2015.
- Wrapped foods: FYTTE (dietitian-reviewed) and オリーブオイルをひとまわし.
- Kalogeropoulos N, Andrikopoulos NK, Hassapidou M. “Dietary evaluation of Mediterranean fish and molluscs pan-fried in virgin olive oil.” 2004.
- Nutrition Research and Practice 19(6), 2025: fat lost from grilled pork belly.
- USDA FoodData Central, SR Legacy: raw potato (170026), potato chips (169677), raw pork belly (167812). We used these compositions to check the chip and pork belly figures.
Marinades
- Tkacz et al. Meat Science, 2021: beef marinated 24 h at 4 °C, 3.3–4.4% uptake.
- Fencioglu et al. Foods, 2022: beef steak in vinegar marinades for 2 h, 3.1–4.1% uptake.
- Rahman et al. Food Quality and Safety, 2023: review; tumbled chicken about 6%.