A study of over 260,000 people has shown that those who drink more than 4 cans of fizzy drinks a day are 30% more likely to suffer from depression, and a similar amount of sugary fruit squashes raised the risk by 38%, compared to those who drink no fizzy drinks or fruit squash. The study also showed a higher risk in those who opt for diet versions of these drinks.
This falls in line with a wealth of research linking regular excessive sugar consumption with inflammation. Systemic inflammation has been linked to obesity and chronic illness, including cancer and heart disease, as well as increasing the risk of depression by up to 33%, as evidenced in a 2013 study of 73,000 Danes.
Perhaps surprisingly, those who drank 4 cups of unsweetened coffee a day had a 10% lower risk than those who drank none. Indeed, unsweetened, black coffee has been shown in a number of recent studies to offer health benefits. However, it is important to remember that coffee beans are heavily sprayed with pesticides, may deplete important electrolytes, and disrupt our production of delta 6 desaturase (D-6-D), the enzyme that helps us to convert and utilise omega 3 and 6 essential fatty acids. This evidence suggests drinking coffee in moderation is probably best for overall health.