Terms of Use

Beta version · In effect since September 10, 2026 · Last updated: October 9, 2026

The changes about phone sign-in (signing in with a number and an SMS code instead of Google and Apple) take effect on September 28, 2026. Until that date, existing accounts remain governed by the previous version of these Terms.

These Terms of Use govern your use of the FuelBalance app (Android and iOS) and of the site https://fuelbalance.app, and apply from the date above. Please read them carefully. The highlighted passages, in the boxes, are the ones that limit your rights or let us make decisions about your account. They are in sections 3, 4, 7, 9, 10, 13, 15, 17, and 21.

#Summary

• FuelBalance is offered by Paulo F O de Souza, an individual entrepreneur (empresário individual) (CNPJ 61.942.112/0001-56). Contact: contact@pfengineer.tech.
• FuelBalance is in beta and is free. It may have flaws, and features may change.
• It is for people 18 or older only. The app does not yet verify age.
• It is not a medical or nutritional service. The calorie and macronutrient estimates may be wrong.
• The app uses Google's AI (Gemini) to analyze meals and to power Fuel.IA and the daily insight. Today you cannot turn it off.
• Connecting Strava is optional, and Strava has its own terms. Today there is no button in the app to disconnect Strava.
• To delete your account, write to contact@pfengineer.tech. We reply and complete the deletion within 15 days.
• Nothing in these Terms takes away rights that the Consumer Protection Code (CDC) guarantees you. Brazilian law applies, and you may go to court in the venue of your own domicile.

#1. Who offers FuelBalance

FuelBalance is offered by PAULO F O DE SOUZA, an individual entrepreneur (empresário individual), trade name PF Engenharia de Software e Arquitetura, enrolled under CNPJ 61.942.112/0001-56, with address at Rua José Santos Junior, 169 – Campo Belo – São Paulo/SP – CEP 04609-010. He also uses the PFEngineer brand. In these Terms, "FuelBalance", "we", and "us" refer to him.

Contact for everything (support, privacy, account deletion, and complaints): contact@pfengineer.tech. Requests are handled manually. We reply to and complete requests — questions, complaints, account deletion, and requests about your data, such as receiving a copy or erasing the data — within 15 days.

#2. How these Terms apply

• On the login screen, the app tells you that, by continuing, you agree to these Terms and to the Privacy Policy, with links to both documents.
• The Privacy Policy (/privacidade/) explains how your data is handled. Its section 5 explains how consent for health data works today: the app does not yet have its own consent screens.
• If you do not agree with these Terms, do not use FuelBalance. If you have already used it, you may request account deletion at any time (section 14).

#3. Beta and price

• FuelBalance is in beta: it is a test version that still changes often and may have flaws.
• FuelBalance is free. No charge will be made unless you expressly sign up for a plan, with the price and conditions stated beforehand.
• Paid plan. When you subscribe to the Pro plan, the price and the period (monthly or yearly) are stated before the purchase, on the screen that sells it. The subscription renews automatically at the end of each period, at the same price, until you cancel. Where you bought is where you cancel: on the website, on the subscription page; in the Android app, under Subscriptions in the Play Store; in the iPhone app, under Subscriptions in Settings. Cancelling stops the renewals and keeps Pro until the end of the period already paid for. Refunds of purchases made in a store follow the store’s rules (Google Play or the App Store); those of purchases made on the website follow the Brazilian Consumer Code, including the 7-day right of withdrawal.

During beta, we may change, pause, or remove FuelBalance features. If we remove a feature you use, or pause it for more than 7 days, we will give you notice as described in section 5 (Notices) at least 15 days in advance, and you will be able to request a copy of your data. The notice may come later, as soon as possible, only when the removal or pause is necessary for security, by legal requirement, or because a supplier has stopped offering the service the feature depends on.

• If we decide to shut down FuelBalance, we will give you notice as described in section 5 (Notices) at least 30 days in advance, and you will be able to request a copy of your data before the shutdown.

#4. Who may use it

FuelBalance is exclusively for people 18 or older. Sign-up asks for your age, but today the app does not check or block anyone who reports being under 18. By using FuelBalance, you declare that you are 18 or older. If the age reported is under 18, or if we learn by other means that the account belongs to someone under 18, we will close the account and erase the data, with the notice provided for in section 13 and as described in the Privacy Policy.

To use FuelBalance you also need to:

• have the capacity to accept these Terms;
• sign in with a mobile number that is yours and can receive SMS;
• use the service for yourself, and not to record another person's data.

#5. Your account

• You sign in with your mobile number and a one-time code sent by SMS, verified by Google's Firebase Authentication. We do not ask for an e-mail or a password. Anyone with access to your phone or SIM card can receive the code: use a password or biometrics on the device, ask your carrier for a SIM PIN, do not share the code with anyone. If you cancel or lose the line, the carrier may reassign the number to someone else, who would then receive the code and get into your account. The app does not yet let you change the number: let us know at the contact e-mail before cancelling the line, so we can change the account's number or delete the account.
• The app does not ask for your name: it shows the name on your Strava account, when connected, or calls you "Athlete".
• Accounts created earlier with Google or Apple can link a mobile number in Settings and then sign in with it, with the same data. A number can only be tied to one account.
• Notices: follow two rules.
  • General changes to these Terms, the Privacy Policy, or the service: we notify by e-mail those who have an e-mail on their account and publish the notice at https://fuelbalance.app, with the same advance notice.
  • Notices about your own account (content removal, suspension or termination, sections 9 and 13, and an account belonging to someone under 18, section 13 of the Privacy Policy): go to the account's e-mail, when it has one. Accounts without an e-mail receive the notice by SMS to the account's number. No notice about your own account is published on the site, and periods counted from the notice only start once it is delivered.
• Each account is personal and non-transferable.
• Keep your profile data correct. Incorrect age, weight, and height produce incorrect estimates.
• If you suspect misuse of your account, let us know at the contact e-mail.
• Signing out does not erase your data. You sign out using the exit icon at the top of the Profile screen. The data remains stored in the cloud, and the local copy remains on the phone until you uninstall the app or clear its data. Signing out erases the Strava access keys from the phone. If you share the phone, see section 3.11 of the Privacy Policy.

#6. What FuelBalance does today

FuelBalance is an app for tracking energy balance for athletes. Today it lets you:

• log meals by photo or text, with analysis by Google Gemini's AI, or through the shortcuts in the "Quick" section (gel, bar, sports drink, whey, and banana);
• confirm meals suggested by Fuel.IA in the chat;
• connect your Strava account to import workouts and their estimated calories;
• see the day's balance (calories consumed minus the day's estimated expenditure, which adds the estimated basal metabolism and the calories from workouts) and the history of meals, workouts, and calories;
• log weigh-ins and track the evolution of your weight and body fat;
• receive a daily insight with general recommendations for protein, carbohydrates, and fats and chat with Fuel.IA about nutrition and training.

FuelBalance's content is informational and educational, aimed at sports nutrition and energy balance in general.

What does not exist yet: the "Voice" button on the meal logging screen (Fuel.IA by voice, in the chat, does exist) and integrations with Garmin Connect and TrainingPeaks. Today the only source of workouts is Strava. The following also do not exist today: using the app without the AI, disconnecting Strava from within the app, deleting your account or downloading your data from within the app, deleting weigh-ins from within the app, turning off usage analytics, reporting AI responses, and consent screens. Section 14 of the Privacy Policy shows what to do instead of each of these.

#7. What FuelBalance is not

FuelBalance is not a health service, is not a medical device, and does not diagnose, treat, cure, or prevent any disease or condition. The numbers, insights, recommendations, and Fuel.IA's responses are not a diagnosis, a prescription, an individualized meal plan, or medical or nutritional guidance. FuelBalance is not a substitute for doctors, nutritionists, or physical education professionals.

We recommend that you consult a health professional before starting or changing a diet, training, or weight goals, especially if you:

• have or have had an eating disorder;
• have diabetes, heart, kidney, or metabolic disease, or another health condition;
• are pregnant or breastfeeding;
• take medications that affect appetite, weight, or metabolism;
• intend to lose or gain weight rapidly.

Do not use FuelBalance in emergencies. If you feel unwell, or have pain, dizziness, or another symptom during workouts or diets, stop the activity and seek medical care.

#8. Estimates and artificial intelligence

• The photo and text analyses, the insights, the recommendations, and Fuel.IA's responses are generated by artificial intelligence (Google Gemini). Fuel.IA is not a person.
• Today the AI is not optional. Meal photos and descriptions, messages to Fuel.IA, and a summary of your day are sent to Google, as the Privacy Policy explains (sections 3.4 to 3.6).
• The estimates can be wrong. The AI may identify the wrong food, misjudge a portion, estimate incorrect calories and macronutrients, or give an inaccurate answer. In addition:
  • basal metabolism is estimated by formula, without considering biological sex;
  • workout calories come from Strava, which reports work in kilojoules; the app uses that number as kcal, and activities without that value, such as many runs without a power meter, count as 0 kcal;
  • the home screen's balance subtracts the estimated basal metabolism, but the balance that Fuel.IA and the insight receive does not subtract it, so the numbers may not match (Privacy Policy, section 12);
  • when Gemini does not respond and the app recognizes the dish on the phone, it knows only six common foods; for the rest, the values stay at zero until you correct them;
  • the "Quick" section shortcuts use fixed values, which may differ from the product you consumed.
• Review before saving. In a meal analyzed by photo or text, you can correct the calories and macronutrients of each item and remove items. The name and quantity of the items cannot be edited. Meals suggested in the chat can only be confirmed or discarded.
• Use the recommendations as general reference, with critical judgment and, whenever possible, with professional support.
• Today there is no button to report AI responses. If a Fuel.IA response or an insight is wrong or is offensive or dangerous, write to contact@pfengineer.tech with the date and the text. You may also request, through that e-mail, an explanation of the criteria and a review of an estimate.

#9. Your content and the permission you give us

Your content is everything you send to FuelBalance: meal photos, descriptions, messages to Fuel.IA, weigh-ins, goals, and records.

• The content remains yours. FuelBalance does not become its owner.
• For the service to work, you grant us, as to the copyright in your content, a free, non-exclusive, and revocable permission to store, process, analyze, and display that content to you, including through the suppliers listed in the Privacy Policy, such as Google Gemini. This permission serves only to operate, maintain, protect, and support FuelBalance. It is not consent for the processing of your personal data or for the transfer of that data outside Brazil, which follow the Privacy Policy.
• Shared food database: when you save an item with a quantity in grams, the food's name, the nutritional values per 100 g, and your account's identifier become part of the FuelBalance food database, which other connected accounts can read. Avoid names that identify people. You may request the removal of these entries by e-mail.
• This permission does not authorize us to sell your content, show it to other people (apart from the shared food database described above), use it in advertising, or use it to train AI models.
• The permission ends when you delete the content or the account, with three exceptions: the shared food database entries, which stay there until you request their removal by e-mail; the records that Google keeps for a limited time (Privacy Policy, section 6.1); and the data the law requires us to keep.
• You warrant that you have the right to send the content and that it does not violate other people's rights.

We may remove content that violates the law or section 11. In that case, we will notify you (section 5, Notices) and explain the reason, and you may contest it at the contact e-mail.

Suggestions: if you send us ideas or suggestions about FuelBalance, we may use them to improve the service, with no obligation to pay. This does not include your personal data, which always follows the Privacy Policy.

#10. Strava and other third-party services

Strava

• Connecting Strava is optional. The authorization is done on Strava's own page, and use of Strava follows Strava's terms (https://www.strava.com/legal/terms) and privacy policy (https://www.strava.com/legal/privacy).
• Today there is no button to disconnect Strava in the app. Signing out erases the access keys from the phone, but does not revoke access on Strava and does not erase the data already imported. To revoke access, use Strava's settings (https://www.strava.com/settings/apps). To erase the imported data, write to contact@pfengineer.tech.
• FuelBalance is compatible with Strava, but is not an official Strava product, is not sponsored by it, and does not have its endorsement. Strava is a trademark of Strava, Inc.

Other services

• Google (Firebase Authentication), for SMS login, and Google and Apple, for accounts created earlier with those services. Use of those accounts follows each company's terms. The SMS is delivered by your mobile carrier, according to your plan.
• Google (Firebase and Gemini) and Amplitude, suppliers we chose to provide the service, as described in the Privacy Policy.
• If the app is downloaded from an app store, the store's terms also apply to the download and updates.

If a third-party service becomes unavailable, changes its rules, or ends the integration, the functions that depend on it may stop working or change. In that case, we will notify you as described in section 5 (Notices). This does not reduce our liability to you (section 15).

Strava is not a party to these Terms and gives no warranties about FuelBalance. Strava does not promise that FuelBalance works or is fit for a specific purpose. This clause applies within the limits of the Consumer Protection Code (CDC) and does not reduce FuelBalance's liability to you.

#11. Permitted and prohibited use

You may use FuelBalance to track your own eating, workouts, and goals, in a personal and non-commercial way, or, if you are a professional registered on FuelBalance Pro, to follow in your professional practice the athletes who allowed you, under section 21.

The following is not permitted:

• using FuelBalance for any illegal purpose or one that violates other people's rights;
• sending photos, texts, or messages with illegal, discriminatory, sexual, or violent content or content that exposes other people;
• recording another person's data or creating an account in another person's name;
• trying to access accounts, data, or systems that are not yours, or circumventing security rules and usage limits;
• collecting data from the app, the site, or the food database in an automated way (bots, scraping), overloading the service, or interfering with its operation;
• trying to manipulate the AI into generating illegal or dangerous content or into revealing the service's internal instructions;
• copying, reselling, or commercially exploiting FuelBalance or its responses without our written authorization;
• using the FuelBalance brand in a way that suggests a partnership or endorsement that does not exist.

#12. Availability

• FuelBalance may become temporarily unavailable for maintenance, updates, or due to failures of the internet or of the suppliers we use.
• We work to restore the service and fix errors, but, especially during beta, we cannot guarantee uninterrupted operation or the absence of errors.
• This does not set aside your rights under the Consumer Protection Code (CDC) (section 15).

#13. Suspension and termination

By you: you may stop using FuelBalance at any time and request account deletion, at no cost (section 14).

By us: we may only suspend or terminate an account in these cases: (1) fraud or an attempt to access accounts, data, or systems that are not yours; (2) use that violates the law or endangers the security of the service or of other people, such as attacks, bots, or overloading; (3) an account belonging to someone under 18; (4) a violation of section 11 that you did not correct within the period stated in the notice (section 5, Notices), which is at least 7 days, counted from the notice's delivery; (5) shutdown of FuelBalance as a whole, with the notice in section 3.

• Prior notice: before suspending or terminating, we will notify you (section 5, Notices), explaining the reason, and give you at least 7 days, counted from the notice's delivery, to fix the problem or present your side.
• Exception: in cases (1) and (2), we may suspend the account immediately when this is necessary to stop an ongoing harm. In that case, we will notify you right afterward (section 5, Notices), explaining the reason.
• You may contest any decision at the contact e-mail.
• Your rights over your personal data remain in effect, including requesting a copy of your data during the notice period, before deletion. This also applies when the reason is that the account belongs to someone under 18; in that case, the copy may be requested by the account holder or by the legal guardian.

#14. Account deletion

• Today you cannot delete the account through the app or the site. Request deletion by e-mail to contact@pfengineer.tech, stating the account's mobile number (for older accounts, preferably from the e-mail registered on it); to confirm the account is yours, we follow section 11 of the Privacy Policy.
• We reply and complete the deletion within 15 days. Upon completion, we confirm to the e-mail the request came from what was erased and what could not be erased, as described in section 11 of the Privacy Policy.
• Before deleting, you may request a copy of your data.
• Deletion is final. Once completed, the data cannot be recovered.
• Deleting your FuelBalance account does not delete your Strava, Google, or Apple account and does not revoke access to Strava, which you revoke in Strava's settings.
• The local copy on the phone only disappears when you uninstall the app or clear its data.

#15. Liability

Nothing in these Terms excludes or limits the rights that the Consumer Protection Code (CDC) and other laws guarantee you. If any clause could be read in a way that limits those rights, the law prevails.

To be clear:

• We are liable, under the Consumer Protection Code (CDC), for defects in the service. Failures of the suppliers we chose to provide the service, such as Google and Amplitude, and failures of the integration with Strava do not set aside our liability to you.
• FuelBalance provides estimates and general information, not individual medical or nutritional guidance (sections 7 and 8). Decisions about your eating, training, and health are yours, and we recommend making them with the support of professionals.
• We are not liable for harm caused exclusively by you or by third parties unrelated to FuelBalance, such as someone to whom you handed your unlocked phone, under art. 14, § 3º, II, of the Consumer Protection Code (CDC).
• If you use FuelBalance in violation of these Terms and this causes harm to other people or to FuelBalance, you are liable for that harm, under the law.

#16. Intellectual property

The app, the site, the FuelBalance brand, the logo, the design, the texts, and the software belong to PAULO F O DE SOUZA or are used with authorization, and are protected by law. These Terms give you the right to use FuelBalance for personal use while your account exists and do not transfer any right over these elements.

Third-party trademarks, such as Strava, Google, Apple, Garmin, and TrainingPeaks, belong to their owners.

#17. Changes to these Terms

• We publish each new version at this address, with the update date at the top.

We may change these Terms. When a change alters rights or obligations, we will notify you as described in section 5 (Notices) at least 15 days before it takes effect, explaining what changed. If you do not agree, you may stop using FuelBalance and request account deletion, at no cost.

• If a law or authority requires the change within a shorter period, we will notify you as soon as possible.
• Wording corrections that do not change rights or obligations are published with the new date, without prior notice.
• Changes do not apply to facts prior to them.
• Changes involving the processing of your data also follow section 15 of the Privacy Policy.

#18. Applicable law, venue, and complaints

• These Terms are governed by the laws of the Federative Republic of Brazil, in particular the Consumer Protection Code (CDC).
• If you have any problem, you can talk to us at the e-mail contact@pfengineer.tech. Filing a complaint with Procon, at consumidor.gov.br, or in court is optional and is not a condition.
• You may file a complaint with the Procon in your city or go to court, including the Small Claims Court (Juizado Especial Cível). The consumidor.gov.br (https://www.consumidor.gov.br/) platform only accepts complaints against suppliers registered on it.
• On personal data matters, you may file a petition with the ANPD (https://www.gov.br/anpd/). The ANPD asks that you show that you made the request to us first and that it was not resolved within the deadline.
• The venue of your domicile is elected to resolve any dispute about these Terms. Nothing in these Terms imposes arbitration or prevents you from seeking the Judiciary.

#19. General provisions

• If any clause of these Terms is held invalid, the rest remain in effect.
• If we fail to enforce a rule at some point, that does not mean we have waived it.
• These Terms and the Privacy Policy do not set aside the rights that the Consumer Protection Code (CDC) gives you regarding FuelBalance's information and offers.
• We may make versions of these documents available in other languages. In case of any difference, the Portuguese version prevails.
• You may not transfer your account or these Terms to another person.

#20. Contact

• Supplier: PAULO F O DE SOUZA, individual entrepreneur (empresário individual), trade name PF Engenharia de Software e Arquitetura, CNPJ 61.942.112/0001-56
• Address: Rua José Santos Junior, 169 – Campo Belo – São Paulo/SP – CEP 04609-010
• E-mail: contact@pfengineer.tech

#21. FuelBalance Pro (for dietitians and coaches)

FuelBalance Pro is the web area where a dietitian or physical education professional follows the athletes who allowed them. It is in a closed pilot: a sign-up waits until we clear it — by hand or, when the photo of your council card that you send matches what you gave, at once (Privacy Policy, section 3.21) —, and it is free while the pilot lasts. If it becomes paid, we will give notice first, as section 17 describes.

By signing up as a professional, you:

• declare that you hold an active registration with the council you gave (CRN or CREF) and act within its remit;
• use each athlete's data only to follow them, within what they allowed, and keep it confidential, under the LGPD and your council's code of ethics;
• do not bulk-copy, sell, publish or pass this data on to third parties, and do not try to see anything beyond what the panel shows;
• are responsible for the guidance you give the athlete and for what you do with what you saw: FuelBalance shows information, it does not prescribe (section 7).

The athlete chooses what you see and can take access away at any time, without notice to you; every time you open their data it is recorded for them to see (Privacy Policy, section 3.21).

We may refuse a professional sign-up, or suspend and end access to FuelBalance Pro, if the rules in this section are broken, if the registration given is not confirmed, or if an athlete reports misuse of their data. Once access ends, you no longer see the athletes; your account remains valid for the rest of the app.