Great article on eating disorders this month in the Ensign. It shares great information that may be helpful to you if you think there may be a problem with someone you know and love. 

Here are some warning signs to watch for in yourself or loved ones:

A change in weight not related to a medical condition

Severe dieting, binge eating or preoccupation with food

Intense fear of being "fat"

Evidence of forced vomiting

Abuse of laxatives, diuretics, enemas, diet pills, or other related medication

Distorted body image; preoccupation with body shape and size

Obsessive or excessive exercise

Depressed mood or anxiety...

Help for Friends and Family of those who struggle:

Eating disorders affect both men and women of various age-groups.
Eating disorders are typically based on feeling such as powerlessness, anxiety, and shame.
Don't be afraid to discuss worries early on, but realize that a loved one may display warning signs such as preoccupation with body image and yet not be developing an eating disorder.
Try using "I" statements instead of "you" statements that may reinforce feelings of shame.  For example, instead of saying "You can't keep forcing yourself to vomit after meals," say, "I am concerned that you are forcing yourself to vomit after meals."
Be caring but firm.  For example, don't promise never to tell anyone.
Encourage your loved one to seek help, including from therapists and doctors.
Let the person see that although at times you may feel frustration, anger, fear, or helplessness, these feelings don't stop you from loving that person.
Remember that recovery takes time and that the decision to heal ultimately has to come from the one with the disorder.

"Fully accepting our Savior's Atonement can increase our faith and give us courage to let go of constraining expectations that we are somehow required to be or to make things perfect.  We can gratefully accept, as God's sons and daughters, that we are His greatest handiwork!!  Gerrit W. Gong of the Presidency of the Seventy.  Ensign, July 2014, pp. 17