You’ve probably heard that people with prediabetes or diabetes should not eat sweet potatoes because they contain too many carbohydrates and cause insulin and blood sugar spikes. 

That, my friend, is a myth!

You can eat sweet potatoes if you have prediabetes or diabetes. But, you must be cautious of your portion size and the types of food you pair them with. Get this right, and you can avoid the blood sugar spikes that come with eating large quantities of sweet potatoes alone. 

Sweet potatoes are packed with many nutrients and compounds that benefit people with diabetes. So, unless you’re allergic or intolerant, they are an excellent whole food to keep in your diet. 

Keep reading to learn the health benefits of sweet potatoes and how to eat them and maintain balanced sugars even with prediabetes or diabetes. 

The Health Benefits of Sweet Potatoes for People with Prediabetes or Diabetes

Sweet potatoes are one of the most nutritious root vegetables available worldwide. They exist in three colours: white/yellow, orange, and purple. The colour differences are due to the types and amounts of antioxidant compounds they contain.

The orange variety is widely available in the United Kingdom, and the white/yellow type is common in African countries, including Nigeria. Both the white/yellow and purple varieties are easily accessible in East Asian countries, including Japan and China. 

Of all varieties, orange sweet potatoes are the richest source of beta carotenes – an antioxidant that promotes eye and heart health (Neela & Fanta, 2019). People with prediabetes or diabetes have an increased risk of heart disease and eye defects (Mahat et al., 2019; Huang et al., 2017). So, eating sweet potatoes is one way to boost beta carotene intake and maintain these organs.  

Purple sweet potatoes are rich in antioxidants compounds called anthocyanins. Cell culture studies and research in animals and humans show that anthocyanins can reduce insulin resistance and lower fasting blood glucose (Belwal et al., 2017). 

Sweet potatoes are good sources of fibre, which may play a role in regulating blood sugar.

A recent meta-analysis investigating how fibre intake affects blood sugar control in adults with prediabetes or diabetes found people with high fibre intakes had lower glycated haemoglobin (HbA1c), fasting blood glucose, and insulin levels than those with low fibre intakes (Reynolds and Mann, 2020). 

People with high fibre intakes also had lower total cholesterol, triglycerides, low-density lipoprotein (bad) cholesterol, inflammatory markers, body weight and body mass index (BMI) than people with lower intakes (Reynolds and Mann, 2020). 

All varieties of sweet potatoes are also good sources of vitamin C and minerals, including potassium, magnesium, and calcium, vital nutrients for overall health. 

Magnesium is an essential mineral in diabetes because it facilitates carbohydrate processing and makes cells more sensitive to insulin (Alawi et al., 2018). Past research has even shown a link between magnesium intake, insulin resistance and type 2 diabetes.

These studies have shown that people with low magnesium intakes or magnesium deficiencies have a higher risk of developing insulin resistance and type 2 diabetes than those with adequate or higher intakes (Dong et al., 2011). Recent research has further shown that boosting magnesium intake with supplements helps people at risk of diabetes become more sensitive to insulin.

Now you know some of the fantastic health benefits of sweet potatoes, let’s discuss 

How You Can Cook and Eat Sweet Potatoes without Blood Sugar Spikes

Like all foods containing carbohydrates, sweet potatoes will increase your blood sugar levels when you eat them. 

If you have prediabetes or diabetes, the last thing you want is to continuously spike your blood sugar every time you eat, as it can worsen your glucose control and increase your risk of diabetes-related complications. 

While they contain an appreciable amount of carbohydrates, sweet potatoes are a medium glycaemic index (GI) food, meaning that eating a portion of sweet potato that provides around 50g of carbohydrates will increase the blood sugar levels of a healthy person moderately.

 If you have prediabetes or diabetes, the rise might be more significant. 

Your goal is to find a way to eat them to give you the energy and nutrients you need without spiking your blood sugars. 

You can eat sweet potatoes with prediabetes or diabetes without causing blood sugar spikes by serving an appropriate portion size and pairing them with proteins, fats, and leafy vegetables. Proteins, fibre, and fats slow digestion; when combined with carbohydrates, they slow the rate at which the sugars in sweet potatoes are released into your bloodstream and keep your blood sugar and insulin levels stable.

You may have read that baking and frying are the worst ways to cook sweet potatoes if you have prediabetes or diabetes because they spike blood sugars fast. They indeed spike blood sugars more than boiling, but no matter the method you choose, sweet potatoes will spike your blood sugars if you eat them alone in large portions.

The critical point is that you can cook your sweet potatoes the way you enjoy them best, but ensure you adjust your portion size and pair them with proteins, leafy vegetables, and healthy fats. That said, please note that baking and boiling are healthier cooking methods than deep frying.  

If you’re wondering why I haven’t told you the ideal portion size to have, it’s because no one-size-fits-all portion size exists. 

The quantity of sweet potatoes (and carbohydrates in general) you should eat in each meal depends on your age, weight, lifestyle, physical activity levels and unique needs. This portions planner guide can help you determine your needs. 

How Often Can You Eat Sweet Potatoes with Prediabetes?

If you thought you could only eat sweet potatoes once or twice a week just because you have prediabetes or diabetes, you thought wrong!

You can eat sweet potatoes if you have prediabetes or diabetes as often as you wish, even every day if you prefer. However, to keep your blood sugar levels stable, you must eat the correct portions and combine them with quality proteins, fats, and leafy vegetables. 

Here’s a tasty sweet potato recipe to try. 

Spicy Baked Sweet Potato with Spring Greens 

This recipe has an estimated glycaemic load of 18.2, meaning it will raise your blood sugar levels moderately and provide steady energy release. This meal is a rich source of protein, providing 19.2g per portion. It is also a good source of fibre and many essential vitamins and minerals, including:

• Vitamin A (estimated from beta carotenes), providing 1199 mcg or 150% of the daily recommended nutrient intake (RNI)
• Vitamin D, providing 1.8 mcg or 18% of the daily RNI
• Iron, providing 6.5 mg or 47% of the daily RNI
• Copper, 0.31 mg or 31% of the daily RNI

Ingredients

• 2 tablespoons cooked chickpeas
• 1 large egg, boiled

For the sweet potato

• 1 small (82g) sweet potato washed and sliced
• ½ teaspoon olive oil
• ½ teaspoon paprika
• ½ teaspoon cumin
• ¼ teaspoon cayenne
• Pinch of salt 
• Pinch of black pepper

For the spring greens

• 100g spring greens
• 140g cherry tomatoes
• 1 tablespoon tomato puree
• 1 small shallot, finely chopped
• 1 small garlic clove, finely chopped
• 1 teaspoon olive oil
• ½ teaspoon chilli powder
• ½ teaspoon dried thyme
• Pinch of salt
• Black pepper, to taste

Directions

Heat oven to 200C and line a baking tray with baking paper. Combine sweet potatoes, olive oil, cumin, paprika, cayenne, salt, and pepper in a medium bowl. Toss well, then carefully arrange on the baking tray and bake for about 25 minutes or until lightly browned and tender. 

While the potatoes are cooking, start cooking the greens—heat olive oil in a medium non-stick frying pan. Fry the shallots for one minute or until softened, then add the chopped cherry tomatoes, thyme, chilli powder and tomato puree. 

Fry for about five minutes, then stir in spring greens with around two tablespoons of water and season with salt and pepper. Turn the heat down to the lowest and put the lid on the pan. Steam for five minutes or until the greens are tender.

Serve sweet potatoes with greens, boiled egg, and chickpeas. Garnish with chilli flakes if you wish and enjoy!

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