A new rodent study indicated that a Western diet and a high-fat diet promoted similar degrees of obesity in mice, but only the high-fat diet significantly inhibited hypertrophy in response to muscular overload. My interest in p-ratios began with an article back in Volume 5, Issue 1 of the MASS Research Review.
However, “widely accepted” is not synonymous with “known to be true and verified by a robust body of scientific evidence.” With this line of thinking, many have recommended that you should get relatively lean before you try to gain a bunch of muscle, as this will “potentiate” your lean mass gains or allow you to make relatively leaner gains during your bulking phase. In the evidence-based corner of the fitness industry, it’s become widely accepted that high body-fat levels induce insulin resistance, which has an unfavorable impact on p-ratios. So, in general, you’d probably want to have a high p-ratio during a bulk, and a low p-ratio during a cut. Losing a bunch of lean mass but minimal fat mass would result in a high p-ratio during weight loss, whereas losing a bunch of fat mass but minimal lean mass would result in a low p-ratio. P-ratios can also be used for weight loss scenarios, where a high p-ratio actually becomes unfavorable for the typical lifting enthusiast who, presumably, would like to retain lean mass. So, if you gain some weight and almost all of it is lean mass, you’ll have a very high p-ratio if you gain some weight and almost all of it is fat mass, you’ll have a very low p-ratio. In other words:Ĭhange in fat-free mass ÷ change in total body mass = p-ratio This approach quantifies the p-ratio as the proportion of weight that is gained (or lost) as fat-free mass, relative to the total change in body weight. You could use a more complicated equation to calculate a “true” p-ratio value that accounts for energy densities of fat mass and fat-free mass, but for the purposes of this article, we’ll adopt a simple and practical calculation that is more commonly used in the fitness world.
Conceptually, p-ratios are pretty simple when you gain weight, some of the added weight will contribute to the body’s protein reserves (that is, some will be lean mass), and the rest will predominantly be stored as fat mass. If you follow the Stronger By Science Cinematic Universe, then you know we’ve been discussing p-ratios lately.