How to encrypt outgoing connections from a local device? ISPs' throttle internet traffic, so some provide fast lanes for popular websites while all other websites are available to the user at lower internet speeds or bandwith.

I am on an iMac so my question is that is there any way by which I can encrypt outgoing connections from my iMac in-order to escape internet capping
You can get a VPN to automatically encrypt all your traffic, see The best VPNs for Mac OS in 2017 or other recommendation lists for options. It depends on the VPN provider though whether they allow all kind of traffic though, some of them block/throttle torrents for instance. A VPN also doesn't protect you from ISPs throttling all VPN traffic by default.