"Why is this building crowded?"
Your answer: "It's due to too many people inside. Simple as that."
Real answer: There is a popular band inside, which has caused more people to walk into the building in a given 3 hour period than leave it.
The "too many calories" people (you are one of them)all think that the effect of a bad diet (which is often bad caloric partitioning in the body, causing plummeting energy levels as fat cells steal nutrients from the rest of the body, causing a fat person to feel tired and hungry) is also the root cause.
Do kids grow because they eat more? No. They eat more because they are in a growth spurt. Obesity works the same way. A bad diet wreaks havoc on the endocrine system, mainly with insulin levels, causing excessive fat accumulation due to calories being partitioned to fat cells at the expense of the rest of the body. If a person with this kind of caloric partitioning doesn't eat excessive amounts of calories, they will feel tired. If they continue to eat the wrong kinds of foods (foods which continue the bad endocrine reaction) they will continue getting fatter in a feedback loop.
But hey, with advice like yours, you should really go and help others. Go to an insomnia board, and when someone complains of being tired, just say "Insomnia is because you don't get enough sleep. Simple as that."
What a dumb ass.