Which theme this wordpress website is using - extrafatloss.com I have these options - twentytwelve twentyeleven twentythirteen Marketer-Blank-Theme-1.1
This site is using twentythirteen. It's easy to check the theme being used. Simply open the site, press CTRL+U to open source code page. Then search the term "theme" by pressing CTRL+F You will see the theme name next to the searched-term "theme".
That is 2013...can tell by the look. If you ever want to find a theme, try this - http://www.wpthemedetector.com/.
I have had great success with thsi web page that will tell you a theme: http://whatwpthemeisthat.com/ It will also give you a list of any plugins it detects.