Gaining weight in college is pretty easy. I don't want to gain weight, but I can sometimes without meaning to. Just tell your parents you need lunch money every day. Lunches cost about $5 if you get a small one. But instead of spending it on real food, spend it on junk food in the vending machines. You can get a lot of junk on $5. Eat some of it in between classes or during your break. You'll slowly gain without even trying.

Malvineous: Marcus, if there's going to be some guy trying to seek some kind of revenge, it may be best to avoid this. We did NOT come here to start a feud with the people here.
Marcus: Relax, it's probably not that bad. I'm sure she's just frightened. Besides, if she's afraid, shouldn't we help her out here at least until things cool over and she feels better?
Malvineous: Well... I guess that's fine then.
Marcus: Great, can you help us set up the room?
Sally: Thanks so much. I really appreciate it.
Malvineous: So what do you see in a guy like him after just meeting him a few minutes ago?
Sally: Well, for one thing, If he's dedicated enough to travel all the way here from Earth, I know he can take real good care of me.

Malvineous: Marcus, can I speak to you a second?
Malvineous pulls him aside
Malvineous: What are you doing, letting someone come live in our home on the first day of arrival? We're barely settled and we don't have enough means to take care of ourselves, let alone strange women. We don't know anything about her.
Marcus: She's the one who suggested living with us. She's the queen's daughter.
Malvineous: What? They have a queen?
Sally: That's what my mom's friends call her. She's actually the head chairman of the colony central council.

I don't see this as being such a big dillemma. Clearly, she enjoys her current lifestyle, so I would leave her to it. If she doesn't make any effort to lose weight and instead eats in front of the tv, then it's clear that what she really wants for herself the most is to eat and relax. She knows she will gain more weight, and yet she keeps doing it. That shows me that that is what she wants. Just make sure to keep her comfortable and provide food. Women in general say a lot of things they don't mean, so a better way to gauge her meaning is to look at her actions. Here's a handy translation.
WomenSpeak: "I know I should really be losing weight, but... *grabs pizza*"
English: "I love having the freedom of living this way, but I don't want to admit to being a glutton, so I'll call it something else."
Unless she approaches you for a one-on-one discussion about how concerned she is about her health and then lays out a plan for losing weight, I would just ignore her casual weight loss comments and keep pampering her.

Elaine tells Malvineous that it's been fun, but it's getting late and she should get back home. She gives Malvineous a peck on the cheek and heads for the door.
Malvineous: I hope to see more of you soon.
Elaine: Don't worry, you will!
She smiles and the two of them hug their goodbyes before she leaves.

While Marcus and sally are occupied, Malvineous goes into another room in order to stay out of their way. The second woman stands in the doorway.
Elaine: You’re not going to leave me alone with them are you?
Malvineous: I’m sorry, what was your name?
Elaine: Elaine.
Malvineous: Well Elaine, is there anything I can get for you?
Elaine: No, I’m fine, thanks.
Malvineous: I’d better steal some of that food before they eat it all and leave nothing for us. Hold on.
Malvineous grabs what he can carry and brings it back into the other room. The two share it while having a pleasant conversation for an hour.