Here's the science behind this "theory."
(please keep in mind that this is only ONE approach, and is not being labeled as THE approach)
Let’s take a look at a few of the available studies…
* The 12 Day Study
. In a 1996 study, Changes in macronutrient balance during over- and underfeeding assessed by 12-d continuous whole-body calorimetry, researchers found that a 12 day bulk resulted in a 4.38 lean muscle mass gain and a 2 pound fat mass gain. The amazing aspect of the study…participants did not perform any form of resistance training.
BiomedExperts: Changes in macronutrient balance during over- and underfeeding assessed by 12-d continuous whole-body calorimetry.
* The Rochester Study
. The University of Rochester School of Medicine and Dentistry studied the hormonal response to mixed-diet bulking. Results revealed a significant boost in anabolic drive. Participants experienced rocketing levels of insulin, testosterone, and IGF-1, and experienced a significant increase in muscle mass. As in the “12 Day Study”, resistance training was not involved.
Hormonal response to overfeeding -- Forbes et al. 49 (4): 608 -- American Journal of Clinical Nutrition
* The Short Term Study
. In the study, Short-term, mixed-diet overfeeding in man: no evidence for “luxuskonsumption”, following a 13 day caloric maintenance period, 5 male subjects ate bulking diets for a 9 days period. During this time, subjects gained an average of 7.04 pounds. 3.1 pounds of this gain was muscle mass. (Please note that this bulk followed a maintenance period, and not a cut)
Short-term, mixed-diet overfeeding in man: no evid... [Am J Physiol. 1985] - PubMed result