Both previous answers make some good points. And, it sounds like you have a pretty good approach to the matter to begin with. But, if all else fails or you need to really show someone what they are doing so they can see if they are going to achieve a deficit or end up in a surplus, you can try Bodymedia..
I even keep a couple around that I “rent” out for a week or two so people can see what they’re burning vs what they eat. Because it measures heat expenditure, it’s far more accurate than the motion based devices.
Do you know for sure that they gained fat? I noticed that sometimes I would pinch differently. Sometimes more or less. Redo the test 3 times and take an average.
Also if you are using a hand held fat tester. Electronic then they differ so much anyway. Always best to use them in the morning on an empty stomach. Or at least always at the same time and as well take it three times or more and average it out.
that’s always nasty, particularly since it is often accompanied by a reproachful look that insinuates that this is our fault.
I tend to first turn it around and ask whether THEY would have any explanation. Unless there is a medical problem that would explain all of it, an increase in body fat in a person exercising with some regularity probably also means an increase in weight. Clients, with proper introspection, usually will ‘fess up’ and really do not need to hear it from us.
It is a good opportunity to explain how relatively little exercise contributes to the overall equation of ‘energy in vs energy out’, and many exercisers fall into the trap of eating those 300 calories, proudly expended on the treadmill, a few times over in the course of the day. It’s also an opportunity of talking about NEAT, I call it the need to NEAT.
I am curious to read how my colleagues will chime in.