What to Decrease to Lower Blood Sugar
To lower blood sugar levels, tell the person to decrease their total carbohydrate intake, particularly from added sugars and refined grains, while emphasizing whole, minimally processed foods high in fiber. 1, 2
Primary Dietary Modifications
Reduce Total Carbohydrate Intake
- Decreasing overall carbohydrate consumption has the strongest evidence for improving blood glucose control in people with diabetes. 1
- Low-carbohydrate eating patterns (reducing carbs to <26% of total calories) can lower A1c by 0.5% within 6 months. 1, 2
- Each 10% reduction in carbohydrate intake produces measurable decreases in A1c levels, fasting blood glucose, body weight, and blood pressure at 6 months. 1
Minimize Added Sugars and Refined Grains
- Emphasize reducing added sugars and refined grain products, as these cause rapid blood glucose spikes. 1
- While dietary sucrose doesn't raise blood glucose more than equivalent amounts of starch, limiting added sugars remains beneficial for overall glycemic control. 3
- Focus on eliminating sugar-sweetened beverages first, as these provide concentrated sources of rapidly absorbed carbohydrates. 4
Decrease High-Glycemic Index Foods
- Replace high-glycemic index starches (white bread, white rice, potatoes) with lower-glycemic alternatives like legumes, intact whole grains, and non-starchy vegetables. 3
- Although glycemic index effects appear modest in long-term studies, choosing lower-glycemic foods can reduce postprandial glucose excursions. 3
Foods to Emphasize Instead
Increase Fiber-Rich Foods
- Consume at least 14g of fiber per 1,000 calories, with at least half of grain intake from whole, intact grains. 1
- High-fiber diets (up to 50g/day) have been shown to reduce blood glucose in both type 1 and type 2 diabetes, though palatability and gastrointestinal tolerance may limit intake. 3
- Non-starchy vegetables should form the foundation of meals, as they provide volume and nutrients with minimal glycemic impact. 1
Choose Quality Carbohydrate Sources
- When consuming carbohydrates, select high-quality, minimally processed, nutrient-dense sources. 1
- Legumes, lentils, beans, and intact whole grains provide carbohydrates with lower glycemic responses compared to refined alternatives. 3
Weight Management Considerations
Reduce Excess Caloric Intake
- If overweight, decreasing total calorie intake to promote weight loss improves insulin sensitivity and glycemic control. 3, 5
- Prevention of weight gain is desirable, as weight gain adversely affects blood glucose, lipids, and blood pressure. 3
- Fat intake should be monitored in ad libitum diets, as increased fat consumption may promote weight gain and insulin resistance. 3
Alcohol Intake
Limit Alcohol Consumption
- If consuming alcohol, limit intake to one drink daily for women and two drinks daily for men. 3
- Alcohol should always be consumed with food to reduce hypoglycemia risk in those taking glucose-lowering medications. 3
- Excessive alcohol intake raises blood pressure and should be avoided entirely in those with pancreatitis, advanced neuropathy, or severe hypertriglyceridemia. 3
Critical Timing Considerations
Immediate Response (Hours)
- Blood glucose begins rising 30-60 minutes after carbohydrate consumption, peaking at 45-60 minutes. 2
- Restricting sugar produces significantly lower postprandial glucose within the first 2-3 hours compared to high-sugar meals. 2
Short to Medium-Term Response (Weeks to Months)
- Maximum glycemic improvements from carbohydrate restriction occur at 6 months. 2
- Benefits may diminish after 12 months, emphasizing the importance of sustained adherence and ongoing monitoring. 1
Important Precautions and Pitfalls
Medication Adjustments Required
- When decreasing carbohydrate intake, medications that cause hypoglycemia (insulin, sulfonylureas) must be reduced or discontinued to prevent dangerous low blood sugar. 3
- Close monitoring is essential when implementing dietary changes in anyone taking glucose-lowering medications. 3
Contraindications to Very-Low-Carbohydrate Diets
- Very-low-carbohydrate plans should be used cautiously in people taking SGLT2 inhibitors due to ketoacidosis risk. 1, 2
- These restrictive plans are not recommended for pregnant or lactating individuals, children, people with kidney disease, or those at risk for disordered eating. 1, 2
Avoid Overly Restrictive Approaches
- In older adults, especially those in long-term care, imposing severe dietary restrictions risks malnutrition and is not justified. 2
- The goal is sustainable reduction, not elimination, of carbohydrates for most individuals. 1
Complementary Lifestyle Modifications
Increase Physical Activity
- While the question asks what to decrease, it's critical to note that increasing exercise (at least 150 minutes weekly of moderate-to-vigorous activity) significantly enhances the glucose-lowering effects of dietary changes. 1
- Daily exercise prevents more than 2 consecutive days without activity to maintain improved insulin sensitivity. 1