Where the numbers come from

Last updated: 14 September 2026

Cal Clark logs meals. A photo cannot weigh oil in a sauce. We still show our sources, because you should know which number is a draft, which number is from a published nutrition table, and which number you typed yourself.

Photo or a typed description

You take a picture or type what you ate. That leaves your phone, goes to our servers in the EU, and is sent to OpenAI to draft the log.
The draft has food names, a portion in grams, and a first calorie number. If the plate is messy, we may ask one extra question (oil, size, sauce) instead of inventing the rest.
We then check those names against published nutrition tables: first the US government tables, then the German national food table. When the match is confident, we use those published calories and macros for the grams on your draft.
You can change grams or items before the meal counts for the day. Saved meals reuse your number. They do not send the photo again.

Barcode on a packaged product

If you scanned that barcode before, we already have the number.
If it is new, we look it up in Open Food Facts, a public product catalog.
If that catalog has no match, we try FatSecret.
The next scan of the same barcode uses that number. Packaged calories come from the label, not from the camera.

Search

Typed search uses the same published nutrition tables. About 20,700 foods. This is public data. We do not resell it.

Daily calorie budget

Basal metabolic rate uses the Mifflin-St Jeor equation (Mifflin et al., 1990).
Activity uses the Compendium of Physical Activities (Ainsworth et al., 2011).
Minimum calorie floors follow the Dietary Guidelines for Americans (2020-2025).

What this is not

Not medical advice. You confirm every log.
Not a promise that a photo is exact. A photo cannot weigh oil. You confirm the draft.
Not a social network. There is no feed and no one else sees your plate.

Named sources

USDA published nutrition tables
German Nutrient Database (BLS 4.0), published by the Max Rubner-Institut, CC BY 4.0
Open Food Facts
FatSecret Platform API - nutrition information provided by fatsecret Platform API
OpenAI

How we store photos and accounts is on the privacy page.

Official sources, on this page

Cal Clark treats body metrics and meal logs as health-related data. The articles below are the published texts we follow. Official sites do not allow us to show their pages inside ours, so we quote the published wording here.

USDA

United States · public data

Open official source

Published nutrition tables

The US Department of Agriculture publishes calorie and nutrient values for thousands of foods. We keep a copy of those tables on our servers in the EU so a draft can be checked against published numbers. Your photos never go to USDA. Citation: U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, https://fdc.nal.usda.gov.

Quoted from the official publication. Last checked 12 September 2026. · fdc.nal.usda.gov

Official Journal of the EU

EU / EEA / UK GDPR

Open official source

GDPR Article 4(15) and Article 9(1)-(2)(a)

Art. 4(15): 'data concerning health' means personal data related to the physical or mental health of a natural person, including the provision of health care services, which reveal information about his or her health status. Art. 9(1): Processing of personal data revealing racial or ethnic origin, political opinions, religious or philosophical beliefs, or trade union membership, and the processing of genetic data, biometric data for the purpose of uniquely identifying a natural person, data concerning health or data concerning a natural person's sex life or sexual orientation shall be prohibited. Art. 9(2)(a): Paragraph 1 shall not apply if the data subject has given explicit consent to the processing of those personal data for one or more specified purposes.

Quoted from the official publication. Last checked 12 September 2026. · EUR-Lex · GDPR 2016/679