All can be considered one step at a time. Indeed, knowledge itself can be summed up as the ability to recognize a situation and know what to do about it. This the the fundamental aspect of the SBS approach. Data is needed to understand the situation -- the better the data, the better the potential for understanding. Without data, even expertise is just an opinion. With appropriate data, expertise comes alive. Under SBS, knowledge is mapped out so that the best path can be taken when it can make a difference.
The foundations of health are fundamental and complex. Solutions to one person's problems may well make another person's conditions worse. This is less noticeable with young people than with seniors, who have smaller margins of error and less recovery power. The OL approach is to developed targeted guidance based on changing conditions. This may come from the body itself, from the environment and household, and from attitudes and others. Guessing, without having access to such data, is a very expensive and frustrating pastime.