Is USDA FoodData Central free to use?

Yes. FoodData Central is published by the USDA and its data is in the public domain. Direct API access needs a free data.gov key; through fmcg.network your assistant can query it without one.

Are FoodData Central values per 100 g or per serving?

Composition values are per 100 g (or 100 ml). Branded Foods records additionally hold the label nutrients per serving with the serving size the manufacturer declared.

Why does a food have no value for a nutrient?

The nutrient was not analysed for that record or not declared by the manufacturer. Treat a missing value as unknown, not as zero, and try another record or data type.

Can I look up a packaged product by barcode?

Yes, if the manufacturer submitted it to the Branded Foods dataset: search by the UPC or GTIN. Branded Foods is voluntary, so a missing product may simply never have been submitted.

Answers · Updated3 October 2026

USDA nutrient lookup: find nutrients per 100 g and per serving in FoodData Central

Short answer

USDA FoodData Central is the US Department of Agriculture's public food composition register. Search it by food name, brand or UPC, choose one record by its fdcId, and read its nutrients: composition is reported per 100 g (or 100 ml), and Branded Foods records also carry the per serving label values the manufacturer submitted. Always report the record's data type and publication date with any value you take from it.

The data types are different things

Foundation Foods: analytical values for basic foods and ingredients, with documentation of how each value was derived.
SR Legacy: the final release of the USDA National Nutrient Database for Standard Reference, no longer updated.
Survey (FNDDS): foods as reported in the national dietary survey, used for dietary intake studies.
Branded Foods: data submitted by manufacturers, including the label nutrients per serving, serving size and ingredient statement.

How to read a result

A nutrient missing from a record was not analysed or not declared; it is not zero. Branded records are voluntary submissions and carry a publication date, so a value can be older than the current pack. The lookup check returns the fdcId, data type and date with every value so the answer can be traced back to the exact record.

Sources

Run this check in your AI assistant

Add fmcg.network as a connector in ChatGPT, Claude or any MCP client. Read-only checks run without an account.

https://mcp.fmcg.network/mcp

Find a food in FoodData Central

Ask: Use fmcg.network to look up almond flour in USDA FoodData Central and give me protein, fat and fiber per 100 g with the fdcId.

check_id: us_nutrient_lookup__find_food

Agent call

{
  "name": "run_check",
  "arguments": {
    "check_id": "us_nutrient_lookup__find_food",
    "arguments": {
      "query": "almond flour"
    }
  }
}

Nutrients per 100 g for one record

Ask: Use fmcg.network to get the full nutrient composition for this fdcId.

check_id: us_nutrient_lookup__get_composition

Agent call

{
  "name": "run_check",
  "arguments": {
    "check_id": "us_nutrient_lookup__get_composition",
    "arguments": {
      "fdc_id": "<fdcId from find_food>"
    }
  }
}

Connect fmcg.network For AI agents us nutrient lookup

Frequently Asked Questions

Is USDA FoodData Central free to use?: Yes. FoodData Central is published by the USDA and its data is in the public domain. Direct API access needs a free data.gov key; through fmcg.network your assistant can query it without one.
Are FoodData Central values per 100 g or per serving?: Composition values are per 100 g (or 100 ml). Branded Foods records additionally hold the label nutrients per serving with the serving size the manufacturer declared.
Why does a food have no value for a nutrient?: The nutrient was not analysed for that record or not declared by the manufacturer. Treat a missing value as unknown, not as zero, and try another record or data type.
Can I look up a packaged product by barcode?: Yes, if the manufacturer submitted it to the Branded Foods dataset: search by the UPC or GTIN. Branded Foods is voluntary, so a missing product may simply never have been submitted.

Not legal advice. fmcg.network returns facts and the sources behind them; your team makes the call.