People commenting on how skinny you are, how much you eat etc.go

Ignore them. What you choose to put in your body is your private concern.

At the end of the day, it is your responsibility to know what is healthy for you. Other people may provide input but they aren't likely to have control over what you eat unless you starve yourself to the point of falling into a coma. It takes experience to figure out what to take from each person. I mostly ignore the comments of obese people because they have a skewed view of what is healthy. I had a pastor who would asked me on a number of occasions, "Have you been putting on weight?" Each time I discovered I had lost weight rather than gaining weight. A deacon once made the comment, "It's easier to keep the weight off than to lose it after you gain it." His comment came out of the blue, so I'm pretty sure it was a polite way of him saying, "You're starting to gain weight." I wish I had listened to him.

People generally don't say anything when you are obese. When you are slightly overweight they tend to say, "You're looking good." When you are at a healthy weight they tend to say, "You don't need to lose any more weight." At lower weights they begin to start asking, "Are you sure you're eating enough?"

The only appropriate response to any of these comments is to say something like "Thank you for your concern." Regardless of whether they are correct in their assessment or not, people who make comments about your weight are generally concerned for you.