This T Nation article by Christian Thibaudeau changed the way I look at cutting:

https://www.t-nation.com/training/destroying-fat

We've all seen Ronnie's 800lbs deadlift 2-3 weeks out from the Mr. Olympia or Johnny Jackson competing in powerlifting 3-4 weeks prior to the Toronto pro (bodybuilding) show. Dorian Yates, Marc Dugdale, Lee Priest, and several others are also proponents of lifting heavy year-round to keep their muscle mass: they don't change their training between the off-season and pre-contest periods.

They let the cardio and diet drop the fat and simply lift weights to preserve muscle mass. It makes sense, too. When in a calories-restricted state, your body will look to drop some muscle tissue to alleviate its daily energy needs. Simply put, muscle is energy-expensive and when there's a shortage of energy (calories and nutrients) it needs a darn good reason to keep it there!

The best way to maintain muscle mass is to give your body a good reason to keep it, and that reason is to lift heavy. Lifting heavy weights requires a lot of muscle tension, and that needs the muscle to be strong. To keep up with the demand, your body will have no choice but to maintain (or even increase) its muscle mass.

Turns out, he, and the rest of those champions, are right. Heavy lifting preserves muscle mass very efficiently. Add gear in the mix and it's practically infallible. Now a lot of my cutting work is 5x5 compounds with high rep isos thrown in, which works very well. If the keto diet is preventing you from training as hard as you possibly can, is it truly worth it?

One of my favorite sayings, although I'm not sure who coined it: "Fat is burned in the fires of carbohydrates."

In my (possibly controversial) opinion, keto is a fad diet for hockey moms who don't care about having serious muscle mass, not bodybuilders and athletes.