Track What You Eat. Understand How Your Body Reacts.
Most people struggle with unexplained bloating, headaches, fatigue, or skin issues after eating—but never know which foods are the culprit. ReactLog correlates your meals and ingredients with symptoms like digestive issues, brain fog, energy crashes, and skin reactions, revealing which foods your body doesn't tolerate.
You're Eating Foods That Make You Feel Terrible—But You Don't Know Which Ones
Your stomach bloats after lunch. You get a headache by 3 PM. You break out in hives. Your energy crashes. You blame stress, sleep, or bad luck. But the real culprit might be what you ate.
The problem is that food reactions aren't always immediate. Some symptoms appear within 30 minutes, others take 6-24 hours to develop. You eat dairy at breakfast and feel fine. Then you eat pizza at dinner and feel awful the next day. Was it the dairy, the gluten, the tomato sauce, the fat, or something completely unrelated? Without tracking, it's impossible to know.
Food sensitivities and intolerances are real and common. Millions of people experience reactions to gluten, dairy, nuts, shellfish, soy, eggs, and countless other foods. Many don't have diagnosed allergies—they just notice their body doesn't tolerate certain foods well. But without data, they keep eating foods that make them sick.
The solution is systematic tracking. Log what you eat and when. Throughout the day, note any symptoms—bloating, gas, headaches, fatigue, skin changes, brain fog, joint pain, or mood shifts. After 2-3 weeks of consistent logging, patterns emerge. You discover which specific foods or ingredients correlate with your worst symptoms, and which foods make you feel your best.
Once you know your triggers, you can make informed choices. You eliminate the foods that harm you and keep the ones that nourish you. You feel better, have more energy, clearer skin, and a functioning digestive system.
How It Works in 3 Steps
Transform guessing into data-driven food decisions.
Log What You Eat
Each meal, record what you ate and the ingredients. Be specific: note the bread type, dairy sources, added ingredients. ReactLog includes a database of common foods and lets you create custom meal entries. Takes 1-2 minutes per meal.
Track Your Symptoms
Throughout the day, log any symptoms you experience: bloating, gas, headaches, fatigue, brain fog, skin reactions, joint pain, mood changes, energy crashes, digestive issues, or any other reactions you notice. Use quick sliders and checkboxes.
Discover Your Triggers
After 2-3 weeks of consistent logging, ReactLog's on-device analytics identify correlations: "Your bloating is 40% worse on days you eat wheat" or "Your energy crashes 8 hours after dairy." You see exactly which foods and ingredients trigger your worst reactions.
Track Everything That Impacts Your Health
ReactLog adapts to your unique food sensitivities and health journey. Track any combination of these:
Meals & Ingredients
Food type, ingredients, portion size, brands, and preparation methods
Digestive Symptoms
Bloating, gas, cramping, diarrhea, constipation, stomach pain, heartburn
Head & Mood
Headaches, brain fog, anxiety, mood swings, difficulty concentrating
Energy & Sleep
Energy crashes, fatigue, sleep quality, wake-ups, afternoon slumps
Skin & Inflammation
Acne, rashes, hives, itching, eczema flare-ups, joint pain, swelling
Specific Allergens
Track common allergens: gluten, dairy, nuts, shellfish, soy, eggs, sesame
Timing & Context
Reaction timing, meal combinations, stress level, sleep quality context
Custom Tracking
Create unlimited custom symptoms and metrics unique to your health
Your Food and Health Data Stays on Your Phone
Why privacy matters for food reaction tracking.
Your food diary reveals deeply personal information: food allergies and intolerances you manage, digestive issues you're dealing with, health conditions you're addressing, and vulnerabilities about your body. You don't want that data on someone else's server.
Traditional food and health apps sell your dietary data to food companies, health insurers, and data brokers. They track which foods you eat to build profiles, target ads, or adjust your insurance rates. ReactLog takes a fundamentally different approach:
- No backend servers — Your food diary and symptoms live on your device only. Period.
- No analytics SDKs — We don't send telemetry about your usage patterns or what you eat.
- No data collection — We have nothing to collect. No servers means no data pipeline.
- No account required — You don't need to create a login. No username, no email, nothing that identifies you.
- Face ID/Touch ID lock — Your food and symptom data is biometrically protected on your phone.
We charge for the app instead of charging you with your privacy. It's a sustainable business model that aligns our interests with yours. We want you to use ReactLog, but we don't want your food data or health information.
Frequently Asked Questions
How do I identify food sensitivities and intolerances?
Track consistently for 2-3 weeks. Each time you eat, log the meal and specific ingredients. Throughout the day, note any reactions—bloating, headaches, skin changes, fatigue, digestive issues, or energy crashes. ReactLog automatically detects patterns and surfaces correlations. For example: "Your bloating is 40% worse on days you eat wheat" or "You experience brain fog 6 hours after dairy." You'll see which foods and ingredients consistently trigger your worst symptoms.
What types of foods and reactions can I track?
Track any food or ingredient. Common ones include gluten, dairy, nuts, shellfish, soy, eggs, grains, and any specific foods you suspect. For reactions, log bloating, gas, headaches, fatigue, brain fog, skin issues, joint pain, digestive problems, mood changes, anxiety, energy crashes, or any physical symptom you experience. ReactLog supports both pre-loaded foods and unlimited custom meal and symptom entries tailored to your unique sensitivities.
How long until I see patterns in my food reactions?
Most users discover meaningful patterns within 2-3 weeks of consistent daily tracking. Some reactions appear immediately (within 30 minutes to 2 hours), while others develop over 6-24 hours. The more detailed you log your meals and symptoms, the clearer the patterns become. Consistency matters more than duration—tracking every day produces better data than sporadic entries. Some users see significant correlations in as little as 10-14 days, while others want 4-6 weeks to feel confident in their patterns.
Is my food diary data private?
Yes, absolutely. ReactLog has no backend servers and zero data collection. Your meal logs, symptom entries, food sensitivities, and all tracking data never leave your iPhone. We use on-device processing only. You can lock the app with Face ID or Touch ID for an additional security layer. Your food diary and health information stays completely private—we have no way to access, sell, or share it.
Can ReactLog help with diagnosed food allergies?
ReactLog helps you track reactions and identify patterns that may indicate food sensitivities and intolerances. However, it is not a replacement for medical diagnosis or allergy testing. If you suspect a food allergy, consult a healthcare provider for proper testing and diagnosis. ReactLog works alongside professional medical care to help you understand your body's individual responses to foods and make informed dietary choices.
Start tracking today.
Discover which foods work for your body. Free during Early Access. No account required. Your food data stays on your phone.