✨ Available in 151 Languages

Weight Loss Calorie Tracker with AI & Science

Science-backed weight tracking & forecast with AI food scanning for calories, carbon footprint, and gluten flags via barcode; plus calorie budgets and calorie deficit

AI Body Preview AI Muscle Rating Weight Forecast Carbon Footprint Gluten Status

Recorded in the app — every screen shown in your language.

Feature tour

See it in action

Swipe through screenshots of the app

Track your weight

Track your weight

Auto-Zoom chart, connected-scale sync and a %-to-goal gauge on one screen.

Fitness tracker sync

Fitness tracker sync

Steps, workouts and weigh-ins arrive on their own — no manual entry.

Weight Forecast

Weight Forecast

Milestone dates for 15D → 1Y, projected from your own trend line.

AI Food Scanner

AI Food Scanner

Photograph a meal, get calories and an instant on/near/over budget verdict.

Activity impact

Activity impact

Burned calories charted against your target across the whole period.

Caloric Deficit & BMI

Caloric Deficit & BMI

Energy balance in plain numbers, with BMI banding beside it.

CO₂e, gluten & macros

CO₂e, gluten & macros

Every scan carries a footprint estimate, gluten flag and macro split.

Fasting & activity

Fasting & activity

Log a fasting window and watch it feed back into the forecast.

Everything in the app

What makes LyteFast different

Science-backed features for sustainable weight management

AI

AI Body Preview

Pick a photo and see a goal-physique visualization. An artistic rendering, not a prediction.

AI

AI Muscle Rating

A 1–100 score for each of 8 muscle groups, an overall rating and a rank from Wood to Olympian.

BASE

Weight Forecast

BASE

Budget-Based Calories

Budget your calories like your finances.

AI

AI Food Scanner

AI

Barcode Scanner

Verified nutrition for packaged items, straight from the label.

BASE

Fasting Insights

Visualize fasting windows — and their direct effect on your weight.

BASE

Calorie Deficit

BASE

Carbon Footprint

BASE

Gluten Status

FREE

Activity Tracking

Sync steps and workouts, or pick from 60 activity types to estimate burn.

FREE

Shareable Progress

Turn any dashboard card into a clean summary image for Messages or Instagram.

The science

Research Backing LyteFast

Peer-reviewed references supporting weight forecasting, energy balance, carbon footprint of diets, gluten detection, nutrition databases, and AI food analysis.

Weight Forecast

Weight forecasting uses predictive models based on energy balance principles to project future weight trends from recent data. Research shows that self-monitoring of weight and calorie intake, combined with trend smoothing to reduce day-to-day noise, helps people understand their trajectory and make timely adjustments. Short-horizon predictive modeling turns your recent trajectory into actionable forecasts that support adherence and long-term habits.

Budget-Based Calories

Pre-set calorie budgets with clear "within budget" or "over budget" feedback help users make informed food choices in real-time. Research demonstrates that this decision-support approach improves adherence to calorie goals by reducing cognitive load and providing immediate, actionable feedback. The simple "spend vs. budget" framework aligns with behavioral economics principles that show people make better decisions when they have clear constraints and instant feedback on their choices.

Calorie Deficit & Energy Balance

Energy balance—the relationship between calories consumed and calories burned—is the primary driver of weight change. Research consistently shows that creating a calorie deficit leads to weight loss, while a surplus leads to weight gain. Visualizing this deficit in real-time helps users understand how their daily choices impact their progress toward goals. The app translates energy balance into plain language, showing the gap between current intake and target, and what changes can close that gap.

AI Food Scanner

Artificial intelligence and machine learning enable automated food recognition from photos, text descriptions, and barcode scanning. Research shows that AI-powered nutrition estimation can provide reasonable accuracy for common foods, helping users log meals more quickly and consistently. The combination of photo analysis, barcode scanning, and text parsing creates multiple pathways for food logging, reducing barriers to self-monitoring and improving adherence to calorie tracking.

Carbon Footprint

Food production accounts for a significant portion of global greenhouse gas emissions. Research shows that different foods have vastly different carbon footprints, and dietary choices can substantially impact environmental sustainability. Tracking the carbon footprint of meals helps users understand the environmental impact of their food choices and make more sustainable decisions. Studies demonstrate that even small dietary changes can meaningfully reduce carbon emissions.

Gluten Detection

For people with celiac disease or gluten sensitivity, avoiding gluten is essential for health. Research shows that even small amounts of gluten can cause symptoms and long-term damage in sensitive individuals. Barcode scanning and food analysis can help identify gluten-containing products, providing quick screening to support gluten-free dietary adherence. While the app provides indicators based on product information, it's important to note that it's an estimator and not a replacement for careful label reading or medical guidance.

What's free, what's not

Core logging is free. Everything else is an optional subscription, managed through your Apple ID.

Free

  • Weight tracking
  • Activity tracking
  • Apple Health sync
  • Share

Base Access

  • Weight Forecast
  • Calorie Deficit
  • Fasting Insights
  • Carbon Footprint
  • Gluten Status

AI Add-On

  • AI Food Scanner
  • Barcode Scanner
  • AI Body Preview
  • AI Muscle Rating

Ready to start your journey?

Download LyteFast today

Download on App Store

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