# I Tested 3 Muscle Building Diets... Only 1 Was Worth It Source: https://www.youtube.com/watch?v=D6Qw2dfrFRg Recap page: https://rapidrecap.app/video/D6Qw2dfrFRg Generated: 2026-02-22T15:30:55.374+00:00 --- ## Quick Overview The Fast Bulk diet proved to be the most effective for building muscle in 90 days, resulting in 4.4 lbs of muscle gain with only 3.4 lbs of fat gain, significantly outperforming the Lean Bulk diet (1.35 lbs muscle / 0.5 lbs fat) and the Main Gain diet (1.1 lbs muscle / 3.7 lbs fat). **Key Points:** - The Fast Bulk diet resulted in the highest muscle gain: 4.4 lbs of muscle over 90 days. - The Lean Bulk diet resulted in 1.35 lbs of muscle gain and 0.5 lbs of fat gain over 90 days. - The Main Gain diet resulted in 1.1 lbs of muscle gain but 3.7 lbs of fat gain, showing the least favorable muscle-to-fat ratio. - The subject, Dayton, started at 32.8% body fat (BF) and finished at 17% BF after 90 days on the Fast Bulk diet. - Calorie targets were set at 2,300 for Main Gain (maintenance), 2,550 for Lean Bulk (+250 surplus), and 2,800 for Fast Bulk (+500 surplus). - Strength gains were highest on the Fast Bulk diet, which correlated with muscle gain, while the Main Gain diet showed the lowest strength and muscle gains. - The video suggests that while bulking strategies lead to faster muscle gain, maintenance calories (Main Gain) can still support muscle growth, especially for individuals who are newer to training or returning after a layoff. ![Screenshot at 00:29: Dayton's final physique after 90 days on the Fast Bulk diet, showing a body fat reduction from 32.8% to 17% and significant muscle development.](https://ss.rapidrecap.app/screens/D6Qw2dfrFRg/00-00-29.jpg) **Context:** This video documents a 90-day experiment where an individual named Dayton followed three different caloric strategies for muscle growth: Main Gain (maintenance calories), Lean Bulk (+250 calorie surplus), and Fast Bulk (+500 calorie surplus). The goal was to determine which diet maximized muscle gain while minimizing fat gain, with progress tracked via DEXA scans, body measurements, and strength testing across the 90-day period. ## Detailed Analysis The experiment tested three diets over 90 days: Main Gain (maintenance calories, 2300 kcal), Lean Bulk (+250 kcal surplus, 2550 kcal total), and Fast Bulk (+500 kcal surplus, 2800 kcal total), all while maintaining the same 5-day per week training program. The results favored the Fast Bulk diet significantly. Dayton gained a total of 4.4 lbs of muscle while only gaining 3.4 lbs of fat over 90 days. The Lean Bulk diet yielded 1.35 lbs of muscle and 0.5 lbs of fat. The Main Gain diet resulted in 1.1 lbs of muscle gain but 3.7 lbs of fat gain. Furthermore, strength gains correlated with muscle gains, with Fast Bulk showing the highest increase in strength. The presenter concludes that the Fast Bulk approach, despite resulting in more fat gain than Lean Bulk, was the most effective overall for maximizing muscle growth in a beginner/intermediate lifter with sufficient body fat, as the extra calories fueled better training performance. Dayton's body fat dropped from 32.8% to 17% over the 90 days. ### 90-Day Transformation Results - Dayton dropped from 32.8% BF to 17% BF; Fast Bulk yielded 4.4 lbs muscle / 3.4 lbs fat; Lean Bulk yielded 1.35 lbs muscle / 0.5 lbs fat; Main Gain yielded 1.1 lbs muscle / 3.7 lbs fat. ### Diet Calorie Targets - Main Gain was set at 2,300 calories (maintenance); Lean Bulk at 2,550 calories (+250 surplus); Fast Bulk at 2,800 calories (+500 surplus). ### Who Should Use Each Diet - Main Gain is for higher body fat lifters (>20%), those returning after time off, or those wanting muscle without bulking; Lean Bulk is for novice/intermediate lifters whose gains have slowed down, or those wanting to stay lean while gaining; Fast Bulk is for naturally skinny lifters, brand new lifters (newbie gains), or those struggling to gain weight. ### Training Intensity - Training intensity remained high across all diets, evidenced by Dayton increasing reps on pull-ups from 7 to 14 and his brother Cole increasing reps on dips from 8 to 12 over 30 days. ### Strength vs. Muscle Correlation - Strength gains matched muscle gains, with Fast Bulk showing the highest muscle and strength increases, followed by Lean Bulk, and Main Gain showing the lowest progress in both metrics. ### Conclusion - Fast Bulk was the most effective for muscle building in this experiment, suggesting that having sufficient body fat and extra calories can optimize muscle growth, even if it means gaining some fat. ![Screenshot at 00:00: Initial comparison showing Dayton on Day 4 of the experiment, starting at a higher body fat percentage.](https://ss.rapidrecap.app/screens/D6Qw2dfrFRg/00-00-00.jpg) ![Screenshot at 00:13: Visual representation of the three diets being tested over 90 days: Diet #1 \(leaner\), Diet #2 \(balanced\), Diet #3 \(higher carb/less whole food\).](https://ss.rapidrecap.app/screens/D6Qw2dfrFRg/00-00-13.jpg) ![Screenshot at 00:31: DEXA scan equipment used to accurately measure body composition changes before and after the diet phases.](https://ss.rapidrecap.app/screens/D6Qw2dfrFRg/00-00-31.jpg) ![Screenshot at 01:22: Formula presented for calculating maintenance calories: Bodyweight \(LBS\) x \(13-16\) = Maintenance.](https://ss.rapidrecap.app/screens/D6Qw2dfrFRg/00-01-22.jpg) ![Screenshot at 04:57: Bar chart comparing muscle vs. fat gain across diets, showing Fast Bulk resulted in the highest muscle gain \(1.8 lbs\) compared to Lean Bulk \(1.35 lbs\) over 30 days.](https://ss.rapidrecap.app/screens/D6Qw2dfrFRg/00-04-57.jpg)