Being attractive matters
One thing i've learned about life that younger people are generally naive about. When we're younger, we're taught that work hard will bring success. For the most part, working hard will never hurt your chances of success. However, the real world is all about superficial things, and it's much easier to be successful if you're attractive or know someone. With making the right connections, it makes it possible for anyone to know someone to get an in, but one of the biggest factors is attractiveness. The most basic way to think about this is this: you can teach someone skills, but you can't teach someone genetics. In the top business schools, almost everyone is attractive. You can teach them how to analyze stock, how to crunch numbers, how to be sociable for clients, but you can't teach genetics. Likewise in my medical school, almost everyone is slightly above average looking to gorgeous. With enough time, you can teach anyone how to be a doctor, but you can't teach everyone how to look good and look appealing to the patient. That's why there's interviews. It's not a way to see who's more qualified. It's a way to see who would be the most desirable (as long as you meet a baseline requirement of course).
In a none academic example: If you're 7 foot tall but have never played basketball before, you best believe some school is going to gamble on you learning how to play and offer you a scholarship. You can teach basketball but you can't teach height. The same applies to looks in the school/job market.
So my advice: when people tell you to get in shape and start to worry about aesthetics, it'll help out in the future.