Your carry-on luggage has to be small enough to fit in the overhead bin. This is a fact, not an opinion.

Even though they sell expandable carry-on bags with all kinds of pockets and pouches and wheels, the laws of physics still apply.  You cannot fill that "carry-on" until it's bursting and then stuff it into the overhead bin on a plane.  The airline has a little box right near the check-in and at the gate that your bag has to fit in in order to fit overhead.  Ignoring that little box will not alter physical reality.

If you feed kids high-calorie junk food they will get fat. Then they will get diabetes.

Kids don't need to eat 2,000 calories a day.  If they eat that much (like a happy meal, a bag of doritos, a snickers, a big gulp and some ice cream) they will gain in excess of a pound a week.  Unless that kid is growing at an astronomical weight or is running around like a Tasmanian devil, s/he is going to be overweight.

Don't do drugs.

Illegal drugs are addictive and unhealthy, but only if you use them.  So don't use drugs. Not even once. It's pretty simple actually.