Diabetes causes blood sugar and glucose levels to either go too low or too high. One of the ways to maintain balanced levels in the body is to have a strict meal plan. While a few food groups are known to not be friendly for those with diabetes, here are some other common yet unsuspecting foods that are a big no-no for those looking to keep their sugar levels in check. Yogurt Yogurt is usually a healthy option but is probably not recommended for those with diabetes. Flavored yogurt sold in the market comes with preservatives and sugar, quickly triggering insulin levels. Dairy is generally not advised for diabetes patients, but having small quantities of homemade yogurt with no flavoring or artificial preservatives is fine.  Cereal Although cereal is something many of us eat in the morning, it's not the best option for those looking to keep their glucose in check. This food comes with added sugars and artificial preservatives that spike sugar levels. Another factor to consider is that cereal and milk make for quite an unhealthy combination, so those with diabetes need to find alternatives to these foods for breakfast. Granola bars Normally sold as a healthy snack, some granola bars are filled with sugar and carbs. Even the dry fruits in them, like raisins, have a high glycemic index. The number of calories in one granola bar may not suit one's daily nutrition requirements. Some bars also have jams, honey, and even chocolate to give them a sweet and distinct flavor.  Bottled smoothies A smoothie made freshly at home is your best bet! The bottled versions sold in the market have a ton of preservatives and sugars to give them their addictive taste. A homemade smoothie with ingredients that do not spike sugar levels is easy to make and good for health. Of course, the amount of yogurt added needs to be moderate. Fruits with a low glycemic index, like peaches, apricots, and kiwi, can be added for better taste. Apart from avoiding the foods mentioned above, those with diabetes need to ensure that calories are regulated in meal plans. An unhealthy lifestyle and poor food choices give way to deeper medical complications. One must speak to a nutritionist and understand the best options for sustainable nutrition.