Do you have symptoms of TMJ or are you worried about preventing it? You want to be sure to keep the strength of your tongue balanced with the strength of your masseters to avoid clenching, bruxism, and joint dysfunction. I've sometimes wondered if my chewing is counterproductive when performed with sub-optimal head/body posture. For example, is it helpful for me to be chewing while lounging on the couch watching TV? I think this relates to an interesting post from @Progress about "backward" vs. "forward" chewing (  /community/community/main-forum/backward-vs-forward-bite/ ). It seems to me that regardless of the head/body posture, chewing will have the effect of exercising and increasing the resting muscle tone of the massetters. However, if chewing also has an influence on repositioning teeth and bones, those effects might be dependent on head/body posture. So I wouldn't recommend waiting to perfect your posture before adding chewing to your routine, but I think it might be better try and practice good posture while chewing.

I have symptoms of TMJ (jaw popping and clicking). Although it isn't painful it is uncomfortable at times. I'm just wondering if chewing could worsen my TMJ? At the same time I know chewing helps with correcting posture but I'm not sure I should continue with the possibility that it could worsen. If I have proper oral posture and body posture most of the time and with proper posture does this mitigate my TMJ although I'm doing serious chewing as well? Or I'm I taking a risk? If you don't mind answering as well, besides gum, what are some foods that I can add to my diet that are more akin to what our ancestors ate that would challenge my jaw muscles? I find it amazing how much more our ancestors chewed but I don't know what exactly they could be eating that would be so much harder on the masseter than modern day.

I suspect marathon chewing sessions could exacerbate your TMJ. I guess if I was in your situation, I would focus more on strengthening your tongue and keeping it on the roof of your mouth. If you want to do chewing exercises, focus on smashing gum against your palate with your tongue, but mix in some regular chewing with your teeth here and there. Correcting that balance between the resting tone of your masseters and tongue might improve your TMJ symptoms, but the downswung alignment of the joint could also be a factor.

I've actually seen cases where heavy chewing has helped people completely fix and heal their TMJ for good. If you are interested I can dig up the screenshots.

I would say to go ahead and give chewing a shot and see how it makes you feel after a few weeks. Just don't overdo it and make sure to listen to your body as you go. It worked for me.