I started eating healthier - more vegetables/proteins, less fat/carbs. My colleague said that I "eat like a woman" ... What should I answer?

Tell him that women usually live longer than men and it may be because they take better care of themselves.

You don't need to answer. It wasn't a question. 

No need to say anything. Be flattered. The implication is that the person who (allegedly) said that, thinks women eat healthier than men. 

I frequently see couples out eating where the lady has a steak and chips and the bloke has a salad.........I'm not sure there are gender-specific diets anymore. Eat what you want. What's it to anyone else? 

I didn’t realize there were such strict gender rules regarding eating