I don't know whether this is for diet products or diet program, but this is diet advertisement that I found anyway. These three versions of the advertisements represent fat women are not considered attractive especially for men. In a lot of societies, a lot of people decide what beauty is, and they evaluate someone through the standards of beauty, which they already set up, what category a woman can be in, as well as a man. If she is considered to satisfy the standards of beauty, she is also considered attractive enough to have attentions from a lot of men, and even some women admire her. In the society, where these advertisements are made, fat women can't awake other people's interests, because they are not considered beautiful and attractive. In the first advertisements, there are well dressed two females and a male, and both women are in front of a man. A fat woman is between another woman and a man, and it seems like that they don't care about her even though a fat woman is in-between them because she is expressed with transparent figure.
In second version, a woman is enjoying taking a sunbath, and a man is running toward her. And I guess that it shows that a man, who has good physical characteristics, doesn't care about her because it looks like he even doesn't realize that she is lying on the sand.
Moreover, in the third version, two men are plying the discus throw even though there is a woman. She is also expressed with transparent figure to represent that a fat woman is not attractive to them. These commercials could be existed because heterosexuality is considered natural/normal/appropriate, and it is predominated concept among a lot of people and societies.
Overall, this advertisement means that a fat woman is not attractive, so she should lose her weight to become attractive enough. Since a woman is expected to date with a man or get married with a man, a woman should have attractiveness and beauty, which are defined by a lot of people and societies/institutes as good (appropriate) enough to appeal to a man. I think that these commercials are based on stereotyped/biased thoughts because physical characteristics are not related to attractiveness of a person.