From 1991 and 1995, adolescent boys in the US, on average, increased their intake of soft drinks from 345 mL to 570 mL. Most soft drinks are sweetened with sugar or corn syrup, and not artificial sweeteners. Dr. David Ludwig of the Boston Children's Hospital showed that school children drinking at least eight U.S. fluid ounces (240 mL) or more of regularly sweetened drinks daily will consume 835 calories (3,500 kilojoules) more than those avoiding soft drinks; i.e., children who drink soft drinks loaded with sugar tend to eat much more food than those who avoid soft drinks. Either those taking sugared drinks lack the same restraint on foods, or sugared drinks cause a rise in insulin that makes adolescents more hungry, causing them to eat more. Soft drinks (including diet soft drinks) are also typically consumed with other high-calorie foods such as fast food. Children who drink soft drinks regularly are therefore fatter on average, in addition to being more likely to develop diabetes later in life.
Soft drinks linked to weight gain and type 2 diabetes
In 2004, an eight-year study of 50,000 nurses showed a correlation that suggests drinking one or more sugar-sweetened beverages (such as soft drinks and fruit punches) per day increases one's risk of developing diabetes by 80% versus those who drink less than one such drink per month. This finding was independent of other lifestyle factors. It concludes, "Higher consumption of sugar-sweetened beverages is associated with a greater magnitude of weight gain and an increased risk for development of type 2 diabetes in women, possibly by providing excessive calories and large amounts of rapidly absorbable sugars.
Most soft drinks contain high concentration of simple carbohydrates - glucose, fructose, sucrose and other simple sugars. Oral bacteria ferment carbohydrates and produce acid, which dissolves tooth enamel during the dental decay process; thus, sweetened beverages are likely to increase risk of dental caries. The risk is greater if the frequency of consumption is high
A large number of soft drinks are acidic and some may have a pH of 3.0 or even lower. Drinking acidic drinks over a long period of time and continuous sipping can therefore er ode the tooth enamel.
According to one report, soft drinks with caffeine can disrupt children's sleep and leave them feeling tired during the day.
There has been a hypothesis that the phosphoric acid contained in some soft drinks (colas) displaces calcium from the bones, lowering bone density of the skeleton and leading to conditions such as osteoporosis and very weak bones. However, calcium metabolism studies by leading calcium and bone expert Dr. Robert Heaney determined that the net effect of carbonated soft drinks, (including colas, which use phosphoric acid as the acidulant) on calcium retention was negligible. He concluded that it is likely that colas prominence in observational studies is due to their prominence in the marketplace, and that the real issue is that people who drink a lot of soft drinks also tend to have an overall diet that is low in calcium. (Source: Heaney RP, Rafferty K. Carbonated beverages and urinary calcium excretion. American Journal of Clinical Nutrition 2001,74:;343-347.)
