I run a small business and manage an Instagram page. You don’t...

I run a small business and manage an Instagram page. You don’t have to be that savy or invest that much time or money to have more followers than they do. A lot of the best fitness/nutrition brands execute a much more comprehensive social media strategy.

They may have achieved penetration with product distribution so far but at no point would you say they have they achieved success with online presence via social media that is engaging consumers. I also doubt they have spent much money because this would probably be reflected with more followers - if a celebrity athlete is getting paid to promote your product you would get some more traffic to the Tonik Instagram !
The number of followers you have is not the most important measure of engagement/success, or even investment, but you can be assured with 1300 followers there is minimal.

They have some good digital content; but I’m assuming they have used it through other mediums. You can be very successful without a proper social media presence but I I think these days a comprehensive approach to develop an enduring brand (particularly in the world of fitness/nutrition/lifestyle) should require more investment into social media, particularly as they continue to diversify.