📘 Diet in type 1 diabetes

Yes, you can eat sweets occasionally, if you include them in carbohydrate counting and administer the appropriate insulin [1]. It's preferable to consume them at the end of a balanced meal, when absorption is slowed down by proteins and fats. Simple sweets (sugar, jam) contain 95-100% carbohydrates with very rapid absorption, requiring precise insulin timing [2]. Ideally, you should consume them 15-20 minutes before a peak of insulin action. Chocolate with over 70% cocoa or desserts with nuts and cream have a lower glycemic index due to their fat content [3].

Important is to avoid consuming sweets on an empty stomach or when blood glucose is already above 180 mg/dl (10 mmol/L), situations where the glucose peak would be excessive. Moderate portions (20-30g carbohydrates) are easier to manage than larger meals, which require higher insulin doses, with additional risks of error [1]. Artificial sweeteners (aspartame, stevia, erythritol) are an alternative without glycemic impact [4], but generally cannot completely replace the pleasure and texture of sugar.

There is no mandatory "diabetes diet". You can eat practically any food if you correctly adjust your insulin doses [1]. A balanced diet, Mediterranean or DASH facilitates glycemic control and reduces cardiovascular risk [5]. Basic principles include using complex carbohydrates with low glycemic index [3], sufficient quality proteins, healthy unsaturated fats (e.g. olive oil), minimum 30g fiber daily and limited sodium intake. Regular meals help with predictability of blood glucose and more precise insulin dosing, but you can also live spontaneously, without problems.

Severe restrictions or fad diets (ketogenic, paleolithic, raw vegan) are technically possible, but complicate insulin management and increase the risk of errors and nutritional deficiencies. Dietary flexibility with emphasis on quality, small and repeated quantities, not restriction, improves long-term adherence and quality of life [6]. Consultation with a nutritionist specialized in diabetes offers personalization based on preferences, lifestyle and individual metabolic goals.

Calculation begins with identifying total carbohydrates (not just sugars) from the nutrition label or from tables/apps for foods [1]. You need to use a digital scale initially to measure food quantities as accurately as possible [2]. The basic formula is as follows: total carbohydrates minus half of fiber (if over 5g) = net carbohydrates for insulin calculation; then divide by your personal insulin-to-carbohydrate ratio to get the necessary units. For example, for 60g net carbohydrates with a ratio of 10, 6 units of rapid insulin will be needed.

For complex meals, calculate each meal component separately. For example, 100g of cooked pasta (25g) + tomato sauce (5g) + 30g of bread (15g) = 45g total carbohydrates. You can possibly consider an extended bolus (slightly) for fats from the sauce. Modern apps (MyFitnessPal, Carbs&Cals, Foodvisor) simplify the process through barcode scanning or photographic recognition [2]. Always verify what the app suggests! After a few months of practice, you'll visually estimate standard portions with reasonable error.

Alcohol brings special risk by inhibiting hepatic gluconeogenesis, with risk of hypoglycemia up to 12 hours after consumption [7]. Consequently, there is an increased risk of hypoglycemia, especially after consumption on an empty stomach or combined with physical exercise [8]. Safety limits are 1 unit for women and maximum 2 units for men per day (one unit = 125ml wine, 330ml beer or 25ml spirits). Alcohol is consumed with solid food. Beer and sweet mixed drinks contain significant carbohydrates (10-30g per dose) requiring insulin. Dry wine and simple spirits have minimal glycemic impact.

For more safety, assess blood glucose every hour during consumption and every four hours during the night, consider reducing basal insulin by 10-20% or basal rates (on pump) for the next 8-12 hours, depending on the amount consumed [7], have a snack with complex carbohydrates before sleep (without bolus) and inform those around you about the risk of hypoglycemia which can be confused with alcohol intoxication [8]. Never consume alcohol to treat hypoglycemia or when you have ketone bodies present. Medical identification bracelet is essential in various social contexts, especially where you consume alcohol.

Foods with glycemic index above 70 raise blood glucose rapidly, usually in 15-60 minutes [3]. Examples of such foods would be pure glucose (tablets, gel), clear fruit juices (apple, grape), simple sweets (jellies, meringues) puffed rice. For treating hypoglycemia, the rule of 15 recommends 15g fast carbohydrates (3-4 glucose tablets, 120ml juice) with recheck after 15 minutes and repeat as needed. Very ripe fruits (banana with spots, watermelon) act in 30 minutes.

Dangerous combinations include simple carbohydrates plus fats, which initially slow absorption then give massive delayed peak (pizza, donuts, french fries with ketchup) [1]. To manage such foods, more complex strategies are needed, with dual or extended bolus. Isotonic sports drinks (6-8% carbohydrates) offer optimal absorption for exercise, and energy gels (20g per pack) are practical for endurance sports. Important is to distinguish between the need for rapid treatment of hypoglycemia (pure glucose) and preventing its recurrence (complex carbohydrates with sustained absorption).

Technically there are no absolutely forbidden foods in modern-treated type 1 diabetes, with an intensive insulin regimen and access to continuous glucose monitoring sensors [1]. However, some foods remain more difficult to manage, such as for example sugar-sweetened beverages (ultra-rapid absorption), pizza/carbonara pasta combinations (fat + carbohydrates => delayed and sustained peak at 4-9 hours) and unfamiliar traditional dishes for you, where you cannot estimate the content. Excessive alcohol remains dangerous through the risk of severe hypoglycemia [7].

Personal food allergies and intolerances (celiac disease is associated in 5-6% of cases [9], lactose intolerance) create individualized restrictions. Ultra-processed foods, rich in additives disrupt the microbiome and increase the general level of inflammation, slightly increasing insulin resistance [10]. Modern recommendation is moderation and variety, not total prohibition. Any food can be included occasionally with planning and careful adjustment of insulin doses. The basis remains quality nutritious food, as little processed as possible.

Strategy begins with studying the menu online before leaving home to estimate carbohydrates and plan various insulin bolus options in advance [2]. Many restaurants have nutritional information available including online. Order sauces and dressings separately if possible, to control the amount (they often contain hidden sugar). Ask for information about preparation methods and main ingredients and don't hesitate to request modifications specially for you. Most chefs are accustomed to special medical requirements of clients. Estimate portions by visually comparing with similar meals from home and add 20% to calculation, for hidden ingredients and expected underestimation.

For insulin timing, you can do 50% of the estimated bolus when you order (anticipating 20 minutes until serving) and the rest when you see exactly the portion. Restaurant meals tend to be rich in fats and sodium, with slower absorption [1]. Consider an extended bolus over 2 hours for large meals. Always keep fast carbohydrates with you (don't rely on dessert) and monitor blood glucose evolution, especially at two and four hours after meal. Here surprises appear most often. Experience gradually gained in the same restaurants allows increasingly better calibration of doses for your favorite foods.

With modern basal-bolus therapy or pump you're no longer constrained to the rigid schedule of old regimens [1]. You can eat flexibly doing meal and correction boluses as the case may be. However, a relatively consistent routine (±2 hours variation) facilitates identification of glycemic patterns and reduces variability, making diabetes management easier. Breakfast at approximately the same time helps manage the dawn phenomenon.

Situations requiring special attention include prolonged fasting (risk of hypoglycemia from excessive basal) [11], meals very delayed compared to usual schedule and shift work (requires different basal profiles for day/night schedule). Maximum flexibility comes with closed-loop pump systems, which automatically adjust insulin delivery for schedule variations. Important is not to skip meals hastily without carefully monitoring blood glucose evolution.

Lack of appetite requires differentiated strategies depending on context. If blood glucose is stable and you don't have significant active rapid insulin (on board), you can postpone the meal by two hours without problems, possibly temporarily adjusting basal rate as needed. If you've already done insulin for the meal, you must consume at least the covered carbohydrates to avoid hypoglycemia. Try light foods such as simple crackers, toast, fruits or beverages with carbohydrates. In case of severe nausea, clear soups, yogurt or simple ice cream could be considered [12].

In case of acute illness with vomiting you need fluids with carbohydrates and electrolytes (50g carbohydrates every four hours), frequent monitoring of ketone bodies, basal insulin without stopping and corrections with rapid insulin (even for moderate blood glucose levels if ketone bodies are present) [12]. Morning nausea can indicate blood glucose too high or too low. Check blood glucose before deciding the solution. Persistence of lack of appetite over two days generally requires medical evaluation beyond adjusting the insulin administration regimen.

Soluble fibers (oats, legumes, apples) form a viscous gel in the intestine, which significantly slows carbohydrate absorption, reducing the postprandial glucose peak [13]. Insoluble fibers (whole wheat, raw vegetables) have less effect on absorption, increase satiety and improve intestinal transit. If a food contains over 5g of fiber, subtract half the fiber amount from total carbohydrates for insulin calculation [1].

Daily consumption of 30g of fiber reduces glycemic variability, improves insulin sensitivity and sometimes slightly decreases total insulin requirement [13]. Sudden increase in fiber quantity in diet can lead to distension and abdominal discomfort. Gradually increase fiber intake, by 5g per week and ensure adequate hydration (fibers absorb water). Fiber supplements (psyllium, glucomannan) taken before meals can reduce glucose peak, but can also interfere with absorption of some medications, if applicable.

Intermittent fasting is possible in the presence of type 1 diabetes, with adequate insulin adjustments and careful monitoring of blood glucose [11]. It is contraindicated in children, adolescents, pregnant women or people with history of eating disorders. During fasting period, basal rate requires temporary reduction to prevent hypoglycemia, and the correction threshold for hyperglycemia increases slightly. Main risk is hypoglycemia at three hours after a meal, because insulin sensitivity is temporarily increased.

Religious fasting (Ramadan) requires individualized insulin adjustments, usually with 20-40% reductions in basal during the last hours of fasting, careful monitoring of blood glucose and ketone bodies, with interruption of fasting in case of hypoglycemia [14]. Total fasting over 24 hours is not recommended [11]. Safer alternative is moderate caloric restriction (750 kcal deficit), maintaining meals and proportional adjustment of insulin doses.

Approved and safe non-caloric sweeteners include stevia (natural, without aftertaste), erythritol (sugar alcohol with minimal absorption, doesn't cause gastric discomfort in normal doses), sucralose (thermally stable for baking), aspartame (except in phenylketonuria) and acesulfame-K (often included in combinations) [4]. Sucrose and large sugar alcohols (maltitol, sorbitol) have at least half the calories of sugar and can raise blood glucose, requiring partial inclusion in carbohydrate calculation. Acceptable daily intake (ADI) of such sweeteners is very hard to exceed normally.

For cooking and baking, erythritol-stevia or sucralose combinations offer texture and volume closest to sugar. In this case, baked goods become slightly denser and dry faster. Taste may require gradual adaptation. Start with partial replacement and gradually increase sweetener proportion. Some sweeteners can cause bloating or diarrhea. Studies suggest possible effects on the microbiome, but with very high chronic consumption [4]. An alternative could be general reduction of sweet preference through gradual exposure to pleasant and less sweet foods.