A recent study from University of California San Francisco found increased sugar in a food supply was linked to higher rates of type 2 diabetes, independent of obesity.
Researches in Japan found sugar to be the greatest predictor of weight gain in men. Every 5g of sugar a man consumed daily resulted in 1/2 lb weight gain that year.
The World Health Organization recommends less than 5% of discretionary calories coming from added sugar. That looks like 6 tsp of sugar or less per day. 1 tbs of ketchup has 1 tsp sugar, 1 can of soda has 10 tsp sugar, 1 packet of maple & brown sugar instant oatmeal has over 2 tsp sugar, and 1 cup of honey nut cheerios has 3 tsp sugar. As you can see sugar intake can add up quickly!
Carbs convert to sugar in the body, so a balance of healthy carbs, healthy fat, and lean protein is needed. It is not healthy to avoid carbs completely. In fact studies consistently show people who eat at least 3 whole grains daily have a reduced risk of diabetes as well as heart disease.
Fruit is natures candy and is part of a healthy balanced lifestyle. A study published in 2008 following 187,382 participants found those who ate whole fruit regularly had a decreased risk of type 2 diabetes. Those who consumed 1 or more servings of fruit juice daily increased their risk of type 2 diabetes as much as 21%.
Enjoy carbs in moderation, cut way back on processed foods, and enjoy fresh vegetables, beans, fruit, quinoa, brown rice, lentils, etc. regularly.
The relationship of sugar to population-level diabetes prevalence: an econometric analysis of repeated cross-sectional data. Basu S, Yoffe P, Hills N, Lustig RH. PLoS One Epub Feb 27, 2013.