Best 21 Days Metabolic Diet Apps

248+ iOS apps curated and reviewed

4.3 avg rating
19 free apps
Updated October 2026

Whether you're new to 21 days metabolic diet or looking for an upgrade, our curated collection of 248+ iOS apps has something for everyone. Each app is reviewed and rated by real users, helping you make an informed decision.

Compare top 21 Days Metabolic Diet Apps (October 2026)

#AppPriceRatingAdsIn-App PurchasesUpdated
121 Days Metabolic Diet21 Days Metabolic Diet$3.993.5★ (2)NoNoOct 2026
2The Fast Metabolism DietThe Fast Metabolism DietFree3.3★ (190)NoNoOct 2026
3The Good Health Guide IThe Good Health Guide IFree2.0★ (1)NoYesNov 2026
4Metabolism Reset DietMetabolism Reset DietFree3.0★ (2)NoNoMay 2026
5Calibrate - Metabolic HealthCalibrate - Metabolic HealthFree4.8★ (5.4K)NoNoNov 2026
6WeightWatchers ProgramWeightWatchers ProgramFree4.8★ (2.4M)YesYesNov 2026
7Gym Faction Workout & Diet AppGym Faction Workout & Diet AppFree4.2★ (5)NoYesOct 2026
8Senior DietSenior DietFree4.5★ (37)NoYesNov 2026

Top Picks for 21 Days Metabolic Diet

The Fast Metabolism Diet screenshot 1

This app supports a 28-day diet plan focused on metabolism boosting without calorie counting. It provides comprehensive food lists, customizable meal planning, and progress tracking tools to help users adhere to the diet's phases and achieve weight loss goals.

What We Love

  • 💻 Easy to use
  • 🔍 Helpful for planning meals
  • 🔔 Useful reminders
  • 💪 Effective for weight loss

Room to Improve

  • 🕰️ Inflexible meal times
  • 📋 Incomplete food lists
  • 🔀 Inconsistent with book
  • 🐛 Buggy and outdated
The Good Health Guide I#3

The Good Health Guide I by 111 (LLC)

Diet, Fitness, Nutrition
Worth Considering
💪 Health & Fitness
2.0(1 ratings)
Free
The Good Health Guide I screenshot 1
The Good Health Guide I screenshot 2
The Good Health Guide I screenshot 3
The Good Health Guide I screenshot 4
The Good Health Guide I screenshot 5

This app provides comprehensive summaries of influential books on diet, fitness, and nutrition. It covers topics like fat loss, metabolism, immunity, and various popular diet plans to help users make informed decisions about their health.

More 21 Days Metabolic Diet apps to explore

FAQ about 21 Days Metabolic Diet

What are the best 21 days metabolic diet apps for iPhone?
21 Days Metabolic Diet tops our 21 days metabolic diet apps ranking as of October 2026, with a 3.5-star average from 2 App Store ratings, and it's priced at $3.99.
Yes — 19 of the top 21 days metabolic diet apps we rank are free to download, including The Fast Metabolism Diet and The Good Health Guide I.
21 Days Metabolic Diet has no ads and has no in-app purchases, according to its App Store listing as of October 2026.
We track 248+ 21 days metabolic diet apps on the iOS App Store as of October 2026, ranked by rating, recency, and analysis of real user reviews.