Does eating sweet potatoes make you fat or lose weight? What is the difference between sweet potatoes and purple potatoes? Finally it's clear

How many people can resist the fragrant sweet potatoes?

Especially in winter, holding a hot baked sweet potato in your arms is a real source of happiness.

There are many different opinions about the effects of sweet potatoes. Some people say eating sweet potatoes can help you lose weight, while others say it can help you gain weight. Some people say sweet potatoes can help you lower blood sugar, while others say they can help you raise blood sugar. There is also a claim that sweet potatoes can help you fight cancer that is circulating online...

So, what is the truth about sweet potatoes? What is the difference between sweet potatoes and purple potatoes? How should we eat them? This article will give you the answers!

Can eating sweet potatoes help you lose weight?

First of all, we need to understand that no food has the real weight-loss function, because there is no negative energy food in the world.

From a nutritional point of view, sweet potatoes, as a type of potato, are staple foods. They have a calorie content of 87 kcal/100 g, while rice has a calorie content of 346 kcal/100 g. Therefore, compared with traditional staple foods such as rice, sweet potatoes have lower calories. That is, under the premise of a fixed stomach capacity, the calories consumed by eating the same amount of sweet potatoes are lower than those of rice. From this perspective, sweet potatoes can help lose weight.

Secondly, sweet potatoes cannot completely replace traditional staple foods. Because staple foods such as rice and flour, although the unit calories are higher than sweet potatoes, their protein content is also high, which is unmatched by sweet potatoes. The protein content in 100g of flour is as high as 13.3g, while the protein content in 100g of sweet potatoes is only about 1.1g. If sweet potatoes are used to replace traditional staple foods for a long time, it is easy to cause malnutrition due to protein deficiency.

There are many reasons for obesity, including genetics, diet, exercise, psychology, and drugs. Even if we only look at dietary factors, the impact of staple food on weight is only a small part of the equation, and total dietary calories are often the key. Even if the staple food is replaced with sweet potatoes, excessive intake of calories from foods other than staple foods can also lead to obesity.

Therefore, it is difficult for us to give an accurate conclusion on whether eating sweet potatoes can help lose weight. The real answer lies in everyone’s three meals a day.

Do sweet potatoes raise or lower blood sugar levels?

Some people say that sweet potatoes raise blood sugar, while others say that they lower blood sugar. Those who say that sweet potatoes raise blood sugar may be because they taste sweeter than rice and steamed buns; those who say that sweet potatoes lower blood sugar may be because they are a coarse grain.

The reference standard for the effect of food on blood sugar is GI (glycemic index). The GI of sweet potatoes is 77, and the GI of rice is 80. Although sweet potatoes taste sweeter than rice, their GIs are similar. From this perspective, both are high GI foods. However, there are many varieties of sweet potatoes, and the cooking methods vary greatly, so the specific effect of sweet potatoes on each person can be judged by blood sugar monitoring.

Do sweet potatoes have anti-cancer effects?

The causes of cancer are very complex, and a healthy diet does help reduce the risk of cancer. But a healthy diet is a whole, not a specific food.

Sweet potatoes are rich in dietary fiber. Like many other foods rich in dietary fiber, eating 50-100g of potatoes every day can promote intestinal motility and improve constipation. However, there is still some controversy as to whether it can help prevent cancer.

The so-called "positive effects" of active substances contained in many foods, including sweet potatoes, on cancer are more of research conclusions at the cellular level, and are far from their "effects" on the human body.

What is the difference between sweet potatoes and purple potatoes?

There are many species in the potato family, and sweet potatoes and purple potatoes have many similarities in nutrition.

First of all, in terms of calories, the calories of sweet potatoes are 87kcal/100g, and the calories of purple sweet potatoes are 133kcal/100g. Although there are differences between the two, they are both low-calorie staple foods. The reason why purple sweet potatoes have higher calories than sweet potatoes per unit weight is that sweet potatoes contain more water than purple sweet potatoes.

Secondly, the dietary fiber content of both is as high as 2.5g-3g/100g, and both are types of food containing high dietary fiber. Eating potatoes regularly can help improve problems such as constipation caused by lack of dietary fiber.

The differences between the two are mainly reflected in micronutrients. For example, the content of lutein in sweet potatoes is higher than that in purple potatoes. This is a fat-soluble compound that has the function of maintaining vision. They are present in the retina, lens and macula of the eye. Lutein and zeaxanthin may help increase the density of pigments in the macula and neutralize harmful free radicals. The content of anthocyanins in purple potatoes is higher than that in sweet potatoes. This is a substance with antioxidant effects. Studies have shown that anthocyanins can promote DNA synthesis and keep cells alive and dividing.

Sweet potatoes and purple potatoes are suitable for people over 2 years old. Potatoes, beans, and whole grains are important sources of carbohydrates for the human body. For modern people who eat too much refined grains, we recommend replacing 30%-50% of them with potatoes, beans, or whole grains to obtain the dietary fiber, B vitamins, minerals, and other food ingredients that are beneficial to the body.

What is the correct way to eat sweet potatoes?

The different cooking methods of sweet potatoes have a great impact on the nutritional value of sweet potatoes. It is recommended that you use steaming, boiling, baking, stewing, or air-drying sweet potatoes as a snack.

It is not recommended to deep-process sweet potatoes such as frying and pulling, because these processing methods will add extra oil and refined sugar to the sweet potatoes, offsetting the original nutritional value of the sweet potatoes.

Expert of this article: Yu Liang, registered dietitian in China, sports nutritionist for the national swimming team

This article was reviewed by Liu Shaowei, Deputy Director and Professor of Food and Drug Regulatory Research Center, East China University of Science and Technology