Hello, Thank you for your query. I appreciate your awareness and efforts to prevent diabetes. Tea is rich in antioxidants and is good for health. Refined sugar or sugar in general is not, especially not more than 2-3 teaspoons a day. Having more than this a day has proven to cause fluctuations in sugar levels in the blood which leads to inflammation & the body being prone to diseases like diabetes, hypertension, heart disease. I would also like to that, omitting entire food groups is not healthy. Diet should include all food groups (protein, carbohydrates, fat) in the right proportions. The idea is to keep metabolism steady throughout the day and not fluctuate too much. Refined grains, processed foods, high sugar containing foods, too much Caffeine, carbonated drinks, alcohol, smoking, sedentary lifestyle and improper sleep habits and stress management are the major culprits for disease. Instead, have whole grains, whole nuts & fruits, vegetables, natural protein sources like fish, egg. Steam or boil foods. Little oil is necessary. Don t feel fry or reuse oil. Get exercise in fresh air, preferably before 10am. Aim at 30-45 minutes for 5 days a week. Have smaller & frequent meals with adequate natural sources of fiber. Inspire of this, genetics can still have the upper hand and result in diabetes. However, your body will be better equipped to deal with this. Diabetes goes hand in hand with hypertension & heart disease. Monitor these parameters regularly. To answer your query, limit your caffeine to two cups a say and sugar to 2-3 teaspoons a day. Hope this helps. Please let me know if there is anything else we can help you with. Wish you continued good health