Actually, I would look in to why the child was a picky eater (whatever that means to you and your family).
Children who are not attaching excessive meaning to food are usually pretty good about supplying their own nutritional needs if the food available is wholesome, varied and not larded with familial meaning, giving the child and the food undue power in the dynamics of the family.
But the article starts off with kids who are goldfish and french fry loving: these foods are made with components designed to addict the consumer (“Betcha Can’t Eat Just One!”). Why in the world would a loving parent feed these PHUDES (looks like food, may even taste or smell like food, but it is not food and does not support life and health) to kids whom they have a responsibility to take care of? Oh, wait! Mom and Dad eat this garbage, too.
OK! So now the problem is what the kid won’t eat because food scientists have addicted the kid to chemicals like MSG (which goes by over a hundred different names) and unregulated the neurological satiety center with fake fats, flavors, etc.?
If the issue is not emotional, then here is the solution: clean up the entire family’s diet and learn, together, what real food is, what it looks, tastes and smells like and what it actually feels like in your body.
Go organic. Make food (in advance, if necessary) and eat it. Together. At the table. In a pleasant setting where eating good, wholesome food is a pleasurable experience. And don’t break training. MacDonalds is a health catastrophe, not a reward!