How Much Muscle Did I Gain In 365 Days? (Scientific Experiment)

Jeff designed this hybrid split to maximize both strength and hypertrophy over the year. The upper and lower days on Monday and Tuesday emphasized heavier loads and compound movements like bench press and squats. After a rest day, the push-pull-legs days allowed for higher volume and more isolation work, taking the last set to failure on everything. The split was maintained for the majority of the year, with only temporary changes like a full-body plan during travel to save time. He emphasized that every exercise in the split was chosen because it maximized hypertrophy ('optimal exercises'), cutting out any filler movements. The program was paired with meticulous tracking of reps and weights to ensure progressive overload.

This was one of the three major training changes Jeff implemented. Before, he would stop compounds 1-2 reps short of failure even on the last set. He acknowledges that for most people, that approach is sensible to manage systemic fatigue and injury risk. However, for the experiment, he wanted to be absolutely certain he couldn't have done more. The protocol was maintained until his knee injury from an isokinetic test, and during the cut he modified it slightly. He believes the relentless effort contributed to breaking his plateau.

Jeff had always tracked his training loosely, but this year he committed to logging every single set and ensuring weekly progression. He notes that during the bulk, his strength shot up consistently, but during the recmp and cut, progress stalled—which is expected. The tracking allowed him to see exactly where he was improving and where he needed to push harder. He later credited this relentless focus on adding weight or reps as a cornerstone of the experiment.

Jeff calculated his maintenance calories and added roughly 15% to create the bulking diet. He and Brad ate the same meals, tracked everything via MacroFactor, and tried to hit their macros exactly. The bulk succeeded in adding lean tissue, but the fat gain was more than Jeff anticipated. He later expressed that he would have aimed for half the weight gain to achieve similar muscle gains with less fat. This protocol is a classic bodybuilding bulk, but his retrospective nuance is a key takeaway.

After the bulk, Jeff wanted to return to his starting weight to accurately measure net muscle gain without the influence of extra body mass. He dropped calories to 2200, which MacroFactor adjusted as his new deficit. Protein was bumped to 190g to protect muscle. He continued to train hard but modified failure protocol on compounds due to injury risk. The cut successfully shed all the 11 lbs gained plus 2 extra lbs of fat, while preserving more than half of the lean mass gained during the bulk.

Jeff highlights that while many focus only on total sleep hours, the regularity of going to bed and waking up also matters. He and Brad both prioritized an 8-9 hour window and tried to keep it stable even with travel. Tracking with Aura rings let them see trends, and Brad's ring even indicated a 4-year improvement in heart health. This sleep protocol was part of the holistic optimization strategy.

Jeff suffered a partially torn quad tendon during a maximal isometric strength test while fasted and without warm-up. He immediately shifted to a rehab protocol: lighter weights, slow tempo (3s down, pause, 3s up). He describes it as 'pales in comparison to the intensity and the load that I'd normally use,' but it kept his quad somewhat active while healing. He later regained strength and even saw net muscle gain in his right quad. This setback highlights how strict optimization can sometimes increase injury risk, and that adaptability is crucial.

Jeff had been lifting for over 15 years and felt he'd stopped progressing, which is typical for advanced naturals. He questioned whether the 'natural ceiling' was even a real phenomenon because no scientific study had directly examined it. By committing to a full year of no skipped workouts, pushing every set to failure, eating perfectly tracked macros, and prioritizing recovery, he was able to add muscle at a body weight he hadn't seen in years. The gains were modest (2.7 lbs lean mass) but visible, especially in his chest and back. He argues that even if a theoretical ceiling exists, most lifters never reach it because their training and nutrition are not truly optimized. He now believes you can slowly push your ceiling upward over time through relentless effort and precision.

After the 6-month bulk, Jeff switched to a recomp phase at his new maintenance calories (2800 kcal). He expected to slowly add muscle and lose fat, but DEXA scans showed a net loss of lean mass. He admits external factors (travel to Mexico and Japan, a switch to full-body training) may have contributed, but he was still training hard and eating high protein. His conclusion is that for someone with his training age, a slight surplus is necessary to drive new muscle protein synthesis; maintenance simply isn't anabolic enough. This is a sharp departure from the idea that recomposition is universally possible. Interestingly, his brother Brad—still a novice—did lose 3.5 lbs of fat and maintained lean mass during the same phase, reinforcing that training age determines whether recomp works.

Jeff used DEXA, ultrasound, and BIA at each check-in. At the end, he was surprised to see BIA claimed he'd lost lean mass, while DEXA showed he gained 2.7 lbs and ultrasound showed quad and bicep growth. He explains BIA has about twice the error margin of DEXA, often failing to detect real changes in experienced lifters whose annual gains are within a few pounds. He emphasizes that the convergence of DEXA, ultrasound, strength tests, and photos confirms real growth, and that people shouldn't feel deflated if a BIA reading disappoints. This is a direct critique of the technology most accessible to consumers.

During the 6-month bulk, Jeff ate a carefully tracked 15% surplus, but ended up with a significant fat gain. While he was pleased to see muscle growth, the fat accumulation was higher than he'd like. He speculated that a smaller surplus—maybe half the weight gain—would have allowed nearly as much lean mass accretion with far less adipose tissue. The reasoning is that muscle protein synthesis is maximized by a certain moderate energy surplus beyond which additional calories just get stored as fat. This insight is particularly relevant for those who want to minimize the harshness of a cut. He still retained most of his muscle after cutting down, so the bulk was not a waste, but he now advocates for a less aggressive approach.

Jeff describes three training changes he made: failure on last set, only optimal exercises, and meticulous progressive overload tracking. The failure protocol meant that on the final set of squats, bench presses, and deadlifts, he would go until he physically couldn't complete the rep, often dropping the barbell onto safety bars. He acknowledges the latest science shows a trend that harder effort yields more growth, but the effect size isn't fully settled. He emphasizes that he still thinks leaving reps in reserve is a good idea for most people, but for his own experiment he wanted to leave no room for doubt. This level of intensity was paired with careful recovery (sleep, deloads). He credits this single-minded aggression as a key factor in his progress.

During a hike, Brad told Jeff that his social anxiety was almost completely gone, and that previously it was debilitating. He described instances of turning around in parking lots rather than enter a store. Jeff was visibly moved and commented that he had been so fixated on muscle gain that he forgot about the many life-changing benefits of lifting. This moment served as a broader lesson for viewers: even if the scale or calipers don't move, training can yield transformative mental and emotional results.