Does your metabolism slow when you hit 30?

I'm a 22-year-old woman. Many of my friends in their late 20s and early 30s (and older) have been warning me about an inevitable metabolism slow-down and subsequent weight gain around my 30th birthday. They say, "You just wait. When I was your age, I sat around all day eating pizza and I never gained a pound. Now I can't lose weight no matter what I do."

I am sure there's some truth to this, but I DON'T sit around eating pizza all day. I run three to four times a week and eat very healthfully. Will these habits ease the slowing down of my metabolism? Or should I expect some weight gain no matter what I do (as they say will happen)?


Do I have a milk allergy or am I lactose intolerant?

This may sound like a dumb question... But I really am unsure. What is the difference between a milk allergy and lactose intolerance? Or are they one in the same? I was in an accident when I was 14. I had emergency surgery on my liver and spleen. After about the age of 20, I have developed severe mad dashes to the restroom after eating anything dairy.

But I have a lot of sinus allergies... that seem to flare up after eating milk products. Although generally milk products do cause thickening of the mucus... I was wondering if severe congestion also goes with it? I no longer eat milk products, of course. But I recently read about a child with a milk allergy who could not breathe through his nose afterward... accompanied by severe coughing. I am now 40 and learned my lesson well... But still curious and always looking for additional info and answers!!


What can I do about salty sweat stains?

I've been a good kid working out and being healthy, but the gym I go to has uniforms and I always wear a black t-shirt. That's great, until I sweat and it leaves salt rings where the sweat reached out to. Ewwww. This is embarrassing, and I have to wash the shirt before I can wear it again, which is annoying since I go almost every day and need to re-wear shirts once or twice. ANYWAYS, how can I reduce the amount of salt in my sweat, and prevent these embarrassing white rings from forming on my clothes? Eating differently, drinking more water, help!