Hey tugs!
I just learned a great piece of information. The smell your wife is experiencing may be due to muscular breakdown. If she is on a low carb diet as well as Xenadrine, like others said through ketosis the the body emits certain chemicals that cause odors, but it is usually through bad breathe. If she does a lot of cardio with weight training, she may be working anaerobically and since she is already burning a lot of fat, her body may be resorting to using muscle as energy during cardio. If this is happening, you'll usually smell an odor resembling amonia. To stop or help prevent this, try HMB, I'm sure you've heard of this. IT's an amino acid and it will help maintain muscle. Also, CLA will help preserve Lean body mass. She can also just cut back on cardio if she does more than three 30 min. sessions.
Sam