11 'Sugar-Free' Traps: Foods That Still Spike Blood Glucose Levels

2. Diet Cereals

Low-sugar or sugar-free cereals can still wreak havoc on your blood sugar. Most use heavily processed grains—corn, rice, or wheat derivatives—that break down rapidly into glucose once digested. Even without added sugar, these cereals often rank high on the glycemic index, delivering a fast spike followed by a mid-morning crash. Marketing terms like “multigrain” or “lightly sweetened” mask the fact that what you’re eating is essentially glucose on a spoon. Without fiber, fat, or protein to slow absorption, your body has little defense. Don’t be fooled by the box—if it crunches like candy, your blood sugar likely agrees.