More Myths Debunked

Water-induced wrinkles are not caused by the skin absorbing water and swelling. They are caused by the autonomic nervous system, which triggers localized vasoconstriction in response to wet skin, yielding a wrinkled appearance. This was theorized to have evolved to give ancestral primates a better grip in slippery, wet environments, but a 2014 study showed no improvement in handling wet objects with wrinkled fingertips.

Hair care products cannot actually repair split ends and damaged hair. They can prevent damage from occurring in the first place, and they can also smooth down the cuticle in a glue-like fashion so that it appears repaired, and generally make hair appear in better condition.

Eight glasses or two to three liters of water a day are not needed to maintain health. The amount of water needed varies by person including weight, activity level, clothing, and environment (heat and humidity). Also, water actually need not be drunk in pure form, but can be derived from liquids such as juices, tea, milk, soups, etc., and from foods, including fruits and vegetables.
Sugar does not cause hyperactivity in children. Double-blind trials have shown no difference in behavior between children given sugar-full or sugar-free diets, even in studies specifically looking at children with attention-deficit/hyperactivity disorder or those considered sensitive to sugar.
A vegetarian or vegan diet cannot provide enough protein for adequate nutrition. Typical protein intakes of ovo-lacto vegetarians and vegans meet and exceed requirements. However, a vegan diet does require supplementation of vitamin B12 for optimal health.
There is little evidence that obesity is related to slower resting metabolism. Resting metabolic rate does not vary much between people. Weight gain and loss are directly attributable to diet and activity.

Breakfast is not the most important meal of the day. Many of the studies about the benefits of breakfast were funded by Kellogg's, and showed correlation, not causation.