Can self-destracting (harming) behavior include eating the wrong food all the time and spending money?

It could. : Especially if you're spending money you don't have or binge eating and purging. Or just binging and then fasting. All patterns of unhealthy behaviours.

Lack of self control: Is a difficult issue to treat. Some people think it is part of an addictive personality disorder with search for immediate gratification.

Yes: It's foolish to medicalize all of people's decisions that we think are unwise. Some people who may be either manic or despondent may eat themselves sick and throw their money away. For extreme cases, getting a physician's help may be key. For the ordinary follies of life, praising what seems to be wise behavior and avoiding overt criticism works best; you can't change most people. Best wishes.