Low-carb eating gets sold as a fit for everyone. It isn't. For plenty of people it's a perfectly reasonable way to eat. For some, cutting carbohydrate changes how their medicine works or how their body copes, and that is worth a conversation before the first meal, not after.
Tap everything that applies to you. Nothing is stored or sent anywhere, and this is a prompt to ask someone, not a medical test.
If anything on that list applies to you, ask a professional before cutting carbs. Medicines are the one that matters most.
Carbohydrate is the nutrient that moves blood sugar the most. If you take insulin or a sulfonylurea (a tablet that makes your body release more insulin) and you suddenly eat far fewer carbs, your dose can become too strong. Diabetes UK says this could send blood sugar too low, and that your diabetes team can advise on changing doses. A different group of tablets, SGLT2 inhibitors, has been linked in case reports to ketoacidosis when taken with very low-carb diets. Ketoacidosis is a dangerous build-up of acids in the blood. It is rare, but it is the reason to ask first rather than adjust on your own.
Blood pressure medicine works the same way in spirit: as your diet, salt and fluid intake change, your pressure can change too, and the dose may no longer fit.
Pregnancy and breastfeeding raise your needs, and published case reports describe serious problems on very low-carb diets while breastfeeding. Anyone with an eating disorder history can be pushed back by rules, counting and cutting out food groups. Kidney, liver, pancreas and gallbladder conditions change how you process protein and fat. Under-18s are still growing. And if you are underweight or losing weight without trying, eating less is not the answer.
Cholesterol is a grey area. Some trials of low-carb and ketogenic diets show LDL cholesterol going up, others don't, and long-term results are conflicting. So if you already have high cholesterol or heart disease, it's worth a conversation. For the wider evidence on weight, see Is low-carb better for weight loss?
Lower-carb eating can be a perfectly sensible choice. A few habits keep it on the safe side:
This guide is general information, not medical advice. If you have a condition, are pregnant or breastfeeding, have or had an eating disorder, or take medication (especially for diabetes or blood pressure), talk to a doctor first. A registered dietitian can build a lower-carb plan around your health.