Should Carbohydrates Be Avoided When Treating Lifestyle Diseases?
Carbohydrates should not be avoided when treating lifestyle diseases like diabetes; instead, focus on consuming high-quality, nutrient-dense carbohydrate sources including vegetables, fruits, legumes, whole grains, and low-fat dairy products. 1
The Evidence Against Carbohydrate Avoidance
Low-carbohydrate diets restricting total carbohydrate to less than 130 g/day are explicitly not recommended in the management of diabetes by the American Diabetes Association. 1 This represents the clearest guideline-level evidence against carbohydrate avoidance in lifestyle disease management.
The American Diabetes Association emphasizes that there is no single ideal dietary distribution of calories among carbohydrates, fats, and proteins for people with diabetes, and meal plans should be individualized while keeping total calorie and metabolic goals in mind. 1 A variety of eating patterns are acceptable for managing type 2 diabetes and prediabetes. 1
Quality Over Quantity: The Critical Distinction
The type and quality of carbohydrates consumed matters far more than the total amount. 1 The total amount of carbohydrate in meals and snacks is more important than the source or type when comparing similar carbohydrate quantities, but this does not mean all carbohydrates are equal in terms of overall health outcomes. 1
Beneficial Carbohydrate Sources
Carbohydrate intake should emphasize nutrient-dense sources that are high in fiber, including:
Studies in healthy subjects and those at risk for type 2 diabetes support the importance of including these carbohydrate-containing foods in the diet. 1
Harmful Carbohydrate Sources to Minimize
People with diabetes and those at risk should avoid sugar-sweetened beverages (including fruit juices) to control glycemia and weight and reduce cardiovascular disease and fatty liver risk. 1 Minimize consumption of foods with added sugar that displace healthier, more nutrient-dense food choices. 1
High consumption of sugar-sweetened beverages increases the risk of obesity and type 2 diabetes, while high dietary fiber intake from whole-grain products reduces these risks. 2
The Role of Carbohydrate Monitoring
Monitoring carbohydrate intake—whether by carbohydrate counting, exchanges, or experience-based estimation—remains a key strategy in achieving glycemic control. 1 This is fundamentally different from avoiding carbohydrates entirely.
For people with type 1 diabetes and those with type 2 diabetes on flexible insulin therapy, education on carbohydrate counting to determine mealtime insulin dosing is recommended to improve glycemic control. 1 For individuals on fixed insulin doses, consistent carbohydrate intake patterns with respect to time and amount may improve glycemic control and reduce hypoglycemia risk. 1
Weight Loss Context: A Nuanced Consideration
While weight loss of ≥5% through calorie restriction and lifestyle modification benefits overweight or obese adults with type 2 diabetes and prediabetes 1, the macronutrient composition can be adjusted based on individual metabolic profiles.
For people with type 2 diabetes on weight maintenance diets, replacing carbohydrate with monounsaturated fat may reduce postprandial glycemia and triglyceridemia, but there is concern that increased fat intake in ad libitum diets may promote weight gain. 1 Therefore, the contributions of carbohydrate and monounsaturated fat should be individualized based on nutrition assessment and metabolic profiles. 1
Recent research suggests that low-carbohydrate eating plans (not carbohydrate avoidance) show potential to improve glycemia and lipid outcomes for up to 1 year in people with type 2 diabetes or prediabetes. 1 One 2022 study found that moderate carbohydrate restriction (30% of energy from carbohydrates) for 6 weeks modestly improved glycemic control and decreased liver fat beyond weight loss effects alone. 3
Common Pitfalls to Avoid
Attempting to eliminate carbohydrates entirely can lead to:
- Decreased intake of beneficial phytochemicals, increasing cardiovascular disease and cancer risk 4
- Reduced consumption of nondigestible carbohydrates (fiber), increasing risk for lower gastrointestinal tract disorders 4
- Depleted glycogen stores, compromising ability to maintain high levels of physical activity 4
- If high in saturated fat, increased LDL cholesterol and worsened endothelial dysfunction 4
The practical approach: Rather than avoiding carbohydrates, focus on reducing refined grains (white bread, white rice, crackers, cereals, bakery desserts), starches (russet or white potatoes), and added sugars (sugar-sweetened beverages, candy) while maintaining intake of protective carbohydrate sources. 1
Special Populations
For individuals with severe hyperglycemia and glucotoxicity, emphasize carbohydrate sources with higher fiber and lower glycemic load while implementing immediate insulin therapy to reverse glucose toxicity. 5 Once glucotoxicity resolves, weight loss through calorie restriction alongside appropriate carbohydrate quality remains essential. 5