Just a note but: it's pretty much been shown through studies, that the worst influence by a huge margin, are TV and movies because girls actually look up at actresses. That article makes a lot of assumptions by drawing lines from TV/movies to games, it seems to me, which is pretty stupid if you understand how the two differ.
For starters, the games that "sin" the most are barely played by girls, games are still clearly fake in design, are often stylized and don't contain real actors for people to grow attached to and look up at. As such, I believe the influence on people is almost zero when it comes to body image.
Fine, let's consider photorealistic games, which are closer to TV and movies.
Here's one study for women: http://www.google.ee/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCwQFjAA&url=http%3A%2F%2Fdmitriwilliams.com%2Ffemalebodies.pdf&ei=C6uaUqGvDtHA7Abs0YD4Ag&usg=AFQjCNGlIs_KBymdKI4nxwqMpbCWbNS0Aw&sig2=XzStI59LyYHbOdCTkZvzPw
The 150 top-selling video games sold in the U.S. across nine platforms were content analyzed to study representations of female bodies. All human females in the games were captured via screenshot and body parts measured. These measurements were then compared to actual anthropometric data drawn from a representative sample of 3,000 American women. The results show that female video game characters at low levels of photorealism are systematically larger than the average American woman whereas female characters at the highest level of photorealism are systematically thinner. This study also found that games rated for children featured females that are thinner than characters in games rated for adults. These findings are discussed in terms of cultivation theory.
Here's one study for men: http://online5.org/download/1119
The 150 top-selling video games were content analyzed to study representations ofmale bodies. Human males in the games were captured via screenshot and body parts measured. These measurements were then compared to anthropometric data drawn from a representative sample of 1120 North American men. Characters at high levels of photorealism were larger than the average American male, but these characters did not mirror the V-shaped ideal found in mainstream media. Characters at low levels of photorealism were also larger than the average American male, but these characters were so much larger that they appeared cartoonish. Idealized male characters were more likely to be found in games for children than in games for adults. Implications for cultivation theory are discussed.
One thing to note in these studies is that the ideal female body is not attainable without major surgery for most women while the ideal male body is attainable for most men. Also, characters with overly muscular bodies are a lot of the times at least somewhat justified by the role of the character and the setting they appear in (Kratos is a Spartan warrior, etc) and much less likely to appear when the setting doesn't justify it.
Oh, and about the effects, how about this study: http://link.springer.com/article/10.1007/s11199-009-9683-8
The present study utilized an experimental design to investigate the short term effects of exposure to sexualized female video game characters on gender stereotyping and female self-concept in emerging adults. Bussey and Bandura’s (1999) social cognitive theory of gender development and differentiation was used to explicate this relationship. Undergraduate students (N = 328) at a large U.S. Southwestern university participated in the study. Students were randomly assigned to play a “sexualized” heroine, a “non-sexualized” heroine, or no video game; then completed an online questionnaire. Female self-efficacy was negatively affected by game play with the sexualized female character. Results cautiously suggest that playing a sexualized video game heroine unfavorably influenced people’s beliefs about women in the real world.
There are more studies that link objectification to eating disorders, sexual dysfunction, greater tolerance of sexual harrassment, etc.