Thanks Jason for taking the time to ask this great question.
Jason writes "Getting older, it seems tougher to keep weight off. I'm doing strenuous bike riding about 1.5 hours (aerobic level with anaerobic intervals) a day 4-5X a week. The weight just doesn't stay off like it used to. I remember my old EMT teacher telling us that when you reach 30, muscle starts going away more quickly. Wendy told me she read that weight lifting is the key to weight loss after 30. Does this mean I will have to start lifting weights to help keep the fat off or is the bike riding with proper feeding going to be enough? I don't like doing weights."
That is a spectacular question. Your old EMT teacher and Wendy are both right. Around the age of 30, we start to loose muscle mass pretty quickly. For most of us, it is about 3% per year, which is pretty rapid! And since muscle burns much more energy at rest then fat, our metabolism slows down according to that muscle loss (and most of us don't slow our eating down). My own body has been a "great" example of this. I have never had an easy time putting on and keeping muscle, but the older I get, the faster its gone. So that's the bad news.
Here is the good news. You don't necessarily have to lift weights to keep your muscle mass. I am guessing you just want to keep the muscle mass, not become a hulking cyclist, so here are some things you will want to experiment with.
-Hills. Lots and lots of long hills. Even increasing your resistance on your bike so you have less aerobic challenge and more strength challenge can help with your legs (although it's likely your legs are not the troubled area as far as muscle loss goes). You can still keep your heart rate up with that, but it will stress your muscles more and convince them to stick around a little longer.
-Yoga. This would be great for your super tight cyclist muscles anyway. It uses your own body weight to increase your strength, while conversely stretching your entire body. You won't gain a lot of muscle mass with yoga, but it will help keep the current muscle mass and prevent such a speedy loss. You will want at least 60 minutes of yoga per week (and more is better, if you can fit it into your routine).
-Push ups, Triceps Dips, and Sit ups/Crunches. These are good because they use your own body weight, you don't have to buy anything to do them and you can get efficient muscle work in about 10 minutes, 3 times per week. As your lower body is probably in great shape already, this is where you will want to focus.
You might have to experiment a little bit to see what works for you, but those are pretty basic ideas to get you started. Hope that helps, Jason!
These tips work for just about anyone hoping to add muscle mass or prevent future loss. Incorporate them into your day and see what changes you notice (you just might be hungrier!).