I do have them keep a food journal. The reason is two-fold. First, it helps keep them accountable for everything they eat and drink. Second, people tend to underestimate the amount of calories amount food and drink they consume, but overestimate how many calories they burn.
I don’t to know calories in the journal, I’m looking for quality of diet and patterns that may be keeping them from their goals. Often times, the clients don’t realize what they need to change in their diet and a fresh set of eyes can help them see that.
Hope that helps.