Should You Worry About Lowering Calorie Intake on Off Days?

If you are on a good resistance training program and training at least 3 days per week (and I argue every one should be doing this for general health), the answer is no. I am starting off answering the question with this supposition to suggest that while constrained TDEE does apply, it does not really come into effect until you surpass the low end of physical activity. 

While resistance training does increase TDEE (total daily energy expenditure), much of it is from the increased metabolic cost of the muscle itself (and yes, I will concede this metabolic cost has been overblown); and the portion attributed to the activity itself seems to spill over enough to the off days that there will be no significant disparity in TDEE between training and off days. 

Let me expand on this. I like to diet myself and others right below the lower threshold of the buffer range. When the goal is a lean mass gaining phase, I like to set the kcal target right above the upper threshold of the buffer range (to avoid unnecessary fat gain). 

I have never really witnessed a trend in how bodyweight changes in an athlete that suggests not lowering kcal intake on an off day (“presumably” because their bodies would have a lower TDEE that day) hindered fat loss. 

And when it comes to a lean mass gaining phase, I HAVE witnessed how bodyweight will spike much more than anticipated from a slight increase in kcal intake because I had (incorrectly) assumed that bc the athlete trained extra hard/long or a large body part that day (e.g. back or legs), their TDEE would be higher than their other more normal training days. And no, it's not due to inflammation and water retention from the extra training stress. Especially when an athlete is lean, a softer physique that persists a couple days after the extra grueling training sessions suggests it's actual fat gain.