A New Site is Looking for Intelligent Feedbacks on Improving Productivity

You might need more social proof. Try sharing content on niche-specific forums. Don't do drive-by spamming though. Actually foster real conversations.

Nice design, site looks good. You are already getting visitors, so that's awesome. Two things that come to mind, which basically apply to any magazine-style website in 2015:

You mentioned that you write all content yourself. Consider including some 'curated' content from personal authority fitness blogs and building relationships with them. The internet doesn't need more information, everything about fitness has been said already a million times and 'writing unique content' gets less and less valuable in today's world. Almost none of the top 500 sites in the world produce their own content, they organize content that already exists in one place. Don't focus too much on SEO, it should be 50% or less of your focus.

Your website lack that 'pull factor' a bit. It has generic, informational articles that have already been talked about on every fitness site and don't have captivating titles.

OTOH if you have articles like 'How I added 30 pounds of muscle in 6 months with only two body-weight exercises I did at home' and sensational-sounding ones like 'Those two guys consume a 10,000 calories cheat meal after their workout. Here's why you should consider doing the same.' There's this 'pull-factor', where everyone visiting the site is like 'Wow interesting' and they click through and through.

Putting articles like "Benefits of carrots" and "Is cardio effective for weight loss" is a huge waste of time, unless you have a concrete purpose in doing it (dropping relevant link in a forum thread where everyone is talking about this). Noone will read those types of articles and if they do it will be on authoritative sites like webmd, not on a site with 20 fb likes (maybe buy some). It doesn't matter if the article is awesome, written by the world expert on carrots and cardio, noone cares.

Also, the money is in the subscribers, not in the visitors (you dont even have an optin). Plenty of people with a ton of traffic but making no money and complaining that they got on the front page of reddit, got 300k visitors but only made $5 with adsense. If you have 10k e-mail subscribers you're set. If you're site is not captivating (like i talked above), you can get million visitors today and tomorrow youll be back to 100.

You can get a ton of fitness traffic from pinterest, I have a site that still makes $200/month from a single pin I posted like two years ago, it promotes a cleansing e-book. Stupid and obviously ineffective easy stuff to lose weight works great there, "The amazing weight loss power of lemon and honey water" and gets repinned a lot. It's a huge community of idiot, but high-income old ladies.

Get on bodybuilding.com and post links after you are green and have lots of posts, etc. careful with the misc

Tons of things to do, writing unique content and getting traffic from gogle is not a good strategy, it will get you to a certain point but itwill be an uphill battle and eventually you roll back down. Even a huge site, like livestrong.com with generic articles, depending on seo will lose 95% of it's traffic if it disappears from google.

Otherwise, great site overall, but you need more controversy, real-life examples and sensational stuff.

Web critiques belong in the Web Design forum.