it makes sense there's only 1% of them. They tend to die faster during famines and hard times. Everybody else has developed the ability to be very efficient with calorie burning.

That was me until I hit 45. Then, you better change your eating habits or buy new jeans. Your size may well change. I also quit smoking, that had an impact on weight too.

Thin does not equal healthy. You will be thin outside, fat inside (TOFI). Visceral fat, fat below the skin and around your organs. Metabolically unhealthy.

OnNe of my sons is, much like one of my brothers, a virtual twig. He eats VORACIOUSLY! I wish I could instill my love for running to him. He could be an incredible long distance runner.

I am 60+ years old, 5'11, and 155 pounds. I eat as much as I want, I just never seem to have much of an appetite. That's been true my entire life. Not sure if that would be called the "thinness gene".

Let’s isolate and package THAT please.

I may have a a touch of that gene. I'm 6'1" and weighed 155 in high school. I worked in a stamping plant in my early 20's. It was fairly physical work and I consumed 4 sandwiches, a small Thermos of soup, an orange and a bag of cookies during my shift. My weight increased to about 170 where it stayed +/- 10# for 40 years.

For years I tried to gain weight. Every meal was a challenge to put away as much as I could. At one point I was working out for 1-2 hours 4 to 5 times a week with fairly heavy (for me) weights and drinking protein shakes. I never quite got to 180. I've more or less given up on trying to gain. The odd thing is that diet and activity level don't seem to have much effect.

I'm not one of those. I'm 6' and 195 lbs and 55 y/o, but I have to really watch what I eat. Shortly after retiring from the Navy I ballooned up to about 240

We are often our own worst enemies.

I was rail thin (5'10'', 125 lbs.) until I was about 40. I drank anything and everything, snarfed up the burgers, fries, sweets, snacks and everything. Never gained an ounce.

My mid-life crisis wasn't all about health, but I knew I had to make changes, so I gave up the booze, the cigarettes, the fried/fast foods, sugary items, and joined a gym. I started lifting weights and put on some muscle, finally getting to about 140 lbs. My body fat percentage dropped from 14% to 11% (muscle weighs more than fat). I started running.

For twenty-five years I stayed at around 140. Then, as age crept in, my endocrine system started to go flaky. I became insulin resistant (a form of Type 2 Diabetes) without realizing it. I gained 30 pounds. In my mind, 175 was a "good" weight for someone who'd been a beanpole his entire life.

But my doctor felt otherwise. I realized I had slipped, and was eating ice cream, pizza, pasta and "easy" foods, but carb-heavy and combined with a knee injury, wasn't burning off the calories. So, once again, I cut back on the food that wasn't good for my body, resumed running, and now at 68 still stand 5'10" and this morning weighed 143 lbs. I check my blood sugar every morning, and while it tends to run on the high side, it's kept me in the pre-diabetic range.

The mirror can lie. Your body doesn't. I stopped being my own worst enemy and regained my health.