However, like all fruits, red grapefruit contains carbohydrates and could potentially increase your blood sugar level depending on how much grapefruit you eat and what other foods you eat with it. (healthyeating.sfgate.com)
What we may not know is that there are large amounts of sugar hiding in other foods we eat every day. (babygaga.com)
The food must be evaluated as a whole — together with other foods eaten at the same time. (sciencedaily.com)