Exercise, never stop. I mean, it's almost embarrassing to talk about how good it is for you ... 13 of the 26 most common types of cancer are lower in people who have higher levels of leisure time physical activity.

There have been, in my 25-year career now at McMaster, probably about two dozen testosterone-boosting supplements that I've seen come and go ... I get DMs on Instagram: 'Which one should I take?' I'm like, save your money. Why bother? Just get to the gym and lift.

15, 20 years ago, if you said you can change the size of your hippocampus and your brain with exercise, I'd have been like, yeah, right. You can. You get improvements in mood. You get improvements in depressive symptoms, anxiety, and everything. You're almost of the magnitude similar to people taking pharmaceutical Interventions for those things.

Up and until probably about 20, 25 years ago, we aimed at a vitamin C intake that prevented scurvy ... But then we've done some science... to show that intakes above the vitamin C intake that prevented scurvy were actually associated with health benefits. And so, we make that recommendation. We haven't done that for protein. We're still aiming at the prevention of deficiency as opposed to optimization of processes that are important.

If you're younger and you're resistance training... 1.6 grams of protein per kilo per day is the type of intake that you need to consume, but the effect is small ... To put it practically, you get most of the benefit from just going to the gym, and then the protein effect is a thin layer on top.

People say, 'What about branched-chain supplements?' ... I think the message is fairly clear now that they're largely, I won't say useless, but from useful to useless, they're a lot closer to the useless end.

Your muscle or your proteins in your body are like a brick wall. The amino acids are the bricks going in; protein synthesis is the bricks going into the wall. But at the other end, there's a process of... bad bricks, damaged bricks, old worn-out bricks being taken out of the wall. So, we're turning protein over constantly. And if you're performing exercise... then that protein turnover process is accelerated. So, you have to put more bricks into the pool to replace the ones that are coming out.

Most people will say that, somewhere in your 30s or 40s, you're beginning to lose muscle mass. My own personal opinion is it's somewhere probably closer to about 56 or thereabouts, but that's personal.

I pay attention to what I eat 80% of the time. And people say, 'Well, what about the other 20%?' I say, that's why I exercise—so I can indulge myself 20% of the time.

You'd like to go into older age when you're beginning to lose muscle at a higher level, because then you're starting the decline from a higher plateau.