Trusting your child with eating is hard. My selective eater is a tall drink of water – he’s always been low on the charts for weight, and top of charts for height. This makes for a sort of physique that closely resembles a medical school skeleton. 
Prior to the DOR, we pressured him to eat out of fear. Other kids in his class were plump by comparison, which we figured out later was the bulk of the problem. He is not built to be plump, while other children are. My son is an individual, not an average of other kids his age. Averages consider the lightest, the heaviest, and everyone in between. The number (the 50th percentile) is the middle of this average, it is not criteria for “a healthy weight.” Normal growth is determined by the individual child’s unique pattern of growth. Small or large can also be normal growth for kids who represent the extremes that make up the weight-for-age average.
There was a period of time when my son’s growth curve slipped. It was at this lowest point in his growth history that we began feeding with trust and following a Division of Responsibility. The problems we were experiencing were not within my son’s ability to solve. It was the environment of fear he was eating in, and my responsibility to remedy, but to do that, I had to learn how. Once we understood that he was not destined for the 50th percentile, we started to be able to trust him to know when he was hungry, and when he full. His growth returned to its regular curve, where he has held steady ever since.
Tonight he ate 1/4 of English muffin for dinner. This isn’t the only thing he’s eaten all day, but before the dawn of trust, it would have caused me great concern. I’m not worried. Years of feeding with trust have taught me that he has a predictable pattern of eating that closely matches his predictable pattern of growth. So I don’t fret over a barely eaten meal like I once did. He is happy, energetic, pleasant and polite – all signs that he can be trusted with eating. 
Kids who are small are difficult to trust with eating, and easy to pressure. Selective eaters are extremely sensitive to pressure; prompts and cues to try to get them to eat more will invariably make them eat less. Be vigilant about keeping pressure away from your table, no matter what shape your child is, and be mindful that you aren’t trying to make them be a shape they were never intended for. If children are able to manage the food offered to them, they can absolutely be trusted with eating.

Addendum: 

Medical barriers to eating must be resolved prior to implementing a feeding strategy based on trust. Deviations from the child’s typical pattern of growth should be discussed with your healthcare provider.