I am often asked whether potatoes can be consumed by people living with diabetes. And I always tell them one simple mantra: If you want to have them, then reduce other carbohydrate-rich foods from your platter, like rice, wheat or any other cereal, and replace them with potato. Don’t have your staple and potatoes together, like aloo dum with roti. And do not tinker with your recommended daily allowance (RDA) for carbohydrates. If you count your calories and use the principle of substitution, you can include potatoes in your diet as an option. WHY POTATOES DON’T WORK FOR PEOPLE WITH DIABETES IN INDIA Potato is a root vegetable, and its starch content is high. Simply put, consuming potatoes is almost equal to consuming rice or wheat. In Western countries, where most of the calories in a standard diet come from fat and protein and very little from carbohydrates, people include mashed potato on the side. In fact, mashed potatoes become an important part of their diet as the consumption of rice and wheat is extremely low. Hence it is alright for them to add carbohydrates in the form of the potato. But in India carbohydrate consumption is very high. The average percentage of carbohydrate consumption in our diet is about 65 to 70 per cent. We hardly consume 10 per cent protein and the rest comes from fat. And then we are used to not having potatoes independently, but always with rice or roti. Several studies have shown that excessive carbohydrates, especially refined carbohydrates, lead to the meal having a very high glycemic index (GI), or the rate at which it can raise blood sugar levels, and glycemic load, both of which are linked to the occurrence of Type 2 diabetes. And among those already diagnosed with Type 2 diabetes, excessive consumption of carbohydrates, which means potatoes and staples, raises their post-prandial sugar levels. It also increases glycemic variation throughout the day when we do continuous glucose monitoring. POTATOES AND A BALANCED DIET Our studies show that even if we cut down carbohydrates by 10 per cent and increase protein to 20 per cent, with the rest of the calories from fat, the combination results in a balanced diet, which helps control diabetes in those who have them, roll back prediabetes and reverse diabetes among those who are in the early stages of the condition. Given that rice is staple of consumption, particularly in the eastern and southern parts of India, and wheat in north India, the bulk of calories comes from these cereals. Hence, we advise patients to cut down on tuberous and starchy vegetables like the potato and instead go for green leafy vegetables, which are fibre-rich and packed with nutrients, vitamins and minerals. My recommended healthy plate has half a pie of low calorie, green leafy vegetables, a quarter for protein and the last quarter for carbohydrates. This carb quarter is filled with either rice or wheat. Just cut that down further and put a potato there. Anything in moderation is okay and it is left to the choice of people living with diabetes to alternate or substitute their carbohydrates but not cross the recommended daily quota. CAN THE METHOD OF PREPARATION HELP? Now some varieties of potato may have a lower GI. Usually it is advised to boil your potatoes and let them cool down before you eat them. That’s because this increases the amount of resistant starch in the potato, which takes time to be digested, keeps you full longer and delays the release of glucose into the bloodstream. The GI can be reduced by 25 per cent through this method of preparation. The best way to have potatoes is to combine them with protein and fibre-rich foods. An Australian study of October 2020 evaluated people with Type 2 diabetes who were assigned to consume dinner with either a boiled potato, roasted potato, a boiled potato cooled for 24 hours or basmati rice (which has a lower glycemic index than a potato). Each meal contained 50 per cent carbohydrate, 30 per cent fat and 20 per cent protein. Results showed no differences in post-meal blood glucose between all three potato-consuming groups. This mix and match works provided you do not raise the total caloric load for the day.
