It's an odd fact, but the more we know about nutrition and health the less we adults seem to take care of our children' physical well being. The evidence for this is overwhelming and it knows no cultural boundaries. The United States may have the highest percentage of unfit, overweight children but the rest of the world is catching up fast.

The problem is much more serious than most parents realize. Unfit children not only run more slowly they learn more slowly too. On this the research is unequivocal: children who are allowed to follow an unhealthy lifestyle have less efficient brains.

This should come as no surprise. After all, we don't expect our cars to run smoothly unless we maintain them properly, so why should we think any differently about our children't bodies and brains? Make no mistake: if you don't look after your child's diet and health she won't be a good learner. And please don't expect your child to take care of this for herself. It's our responsibility as parents to do this; children today may seem more sophisticated and worldly-wise than we were but kids are still kids and they don't often give much thought to healthy lifestyles.

So here are four simple guidelines to ensure that your child is fit to learn:

1. Make sure your child gets enough sleep. Too many children come to school too tired to learn because their parents don't pack them off to bed on time. All teachers know the signs of sleep-deprived children: yawning in class, irritability and lack of concentration. Occasional late nights are no problem for children provided they are allowed to catch up with an afternoon nap, but night after late night spent at the computer or watching DVDs is robbing your child of his right to learn. I use the word 'right'Õ advisedly; children do have rights, of course, and one of them is the right to be sent to bed in time for a good night's sleep!

2. Ensure that your child eats healthy food Ð most of the time at least. Sadly, many parents don't do this. I don't mean that parents should worry too much about the 'latest research'Õ on diet that the newspapers and magazines constantly throw at us. The important thing is to ensure that your child has an adequate intake of proteins, fats, vitamins and carbohydrates. This is achieved by giving your child a variety of foodstuffs. Too much of any one thing is bad. The exceptions to this rule are fruit and vegetables, which you should encourage your child to eat at every mealtime, and for snacks too.
Breakfast is a must for kids. Make sure they eat it, even if they say they don't want to. Remember that hungry kids don't learn in school. One interesting point here, however, is that teenagers have actually been found to have different biological clocks than the rest of us. Teenagers typically come to life later in the day than younger children and adults, whatever time they went to bed the night before. If your teenager can't face breakfast in the early morning, that's normal and healthy. What you should do, therefore, is ask your school to provide a range of healthy snacks at mid-morning recess: that's the ideal time for many teenagers to fuel up with brain food for the day ahead.

3. Keep your child hydrated. Our bodies are mostly made up of water, so if we dry out our organs don't function well, and that includes the brain. Send your child to school with a water bottle and ask your school to ensure that children always have easy access to drinking water. And, yes, water is far better than those sugary drinks that make kids hyperactive and ruin their concentration. The younger you get your child into the habit of drinking water the better.

4. Finally, our children't brains need oxygen. The best way to increase the supply of oxygen to the brain is to take part in physical activity. Teachers know that students work better if they're given short exercise breaks during lessons and if they have a good run around during recess. That expensive play equipment in your school's playground isn't there just for fun Ð it actually helps your child be a better learner. Any exercise is helpful, and that includes weekends. If you allow your child to lie around the apartment all day Saturday and Sunday he won't be ready to learn efficiently on Monday morning. So take your child to the pool with you, or for a walk in the park. Remember: couch potatoes at home are potato heads at school!

To sum up, all children need a good night's sleep, a balanced diet, lots of drinking water and plenty of physical exercise if they are to achieve their full potential at school. We can't expect our children to take care of all this for themselves. It's our responsibility as parents to keep our children fit to learn.