100% of weight loss from muscle

I had my fitness check-in at the gym today, and found out that I had lost 5 pounds in the past month. At first I was really happy! I had lost 8 pounds the month before (lost 14 lbs fat and gained 6 lbs muscle), and lost 5 pounds this month. But then my trainer told me that it was all muscle loss. What?? I looked at the printout for last month and this month, and sure enough, my fat mass had remained exactly the same, even down to the ounce. So all my weight loss was from muscle-- and my body fat percentage was now a bit higher.

I then told my trainer that I am good at tracking calories, and normally am under my caloric limit by ~300 calories (after adding in exercise calories). But I admitted that I haven't been strength training in the past 3 weeks due to work trips but also because I love the aerobic-oriented gym classes. (Normally, I meet with my trainer for 30 min/week and should repeat that routine later in the week -- but I haven't been doing this recently, instead doing aerobic workouts 6-7 times/week.) He concluded that the reason I lost muscle was I wasn't eating enough (which will end up burning muscle) and I wasn't doing strength training. He advised to not go over 200 calories below my caloric limit. Then for our session today, he focused purely on strength training -- when normally he'd have me do a combo of aerobic and strength training stuff.

I know there are different lines of thought here about whether we should eat back our exercise calories, or whether starvation mode exists, and it's true that everyone's BMR, body dynamics, and weight loss goals are different. And, each person is entitled to their opinions and can follow the advice and suggestions of whomever they choose. For myself, however, I trust what my trainer says, and now believe that eating much below my caloric limit will result in muscle loss. I'm also going to add 1-2 strength training workouts a week, and see how this new regimen of eating and exercising impacts next month's fitness check-in test.

If I were to focus purely on the scale numbers, I should be really happy. And I think for most of us, we are elated when we see progress on the scale, and down on ourselves and discouraged when we gain weight. But ultimately, I cannot feel happy about my weight loss, because I sacrificed something more important to attain it. As for my MFP community, of course I want to see you happy with your progress and seeing the scale number going down, but please don't lose sight of the more important health outcomes such as strength, well-being, energy level, and body fat percentage. Also, be careful about making drastic changes to your caloric intake and be thoughtful when setting your weight loss and exercise goals.

Here's to a healthier and stronger us!