In the region of nutrition and health science, there are still many controversies, as I reported before.
One of the current topics, as well as a hypothesis which was continuously believed by many researchers, is the harm of sugar. Rapid intake of sugar makes an increased blood glucose level, leading to resistance to insulin. It results in an onset of diabetes. Restriction of using sugar in the diet is necessary to protect your physical health.
Then, how about starch which is similar to sugar in its chemical structure? Some dietitians recommend you to refrain from taking a large amount of starch as well.
It may be true, but you have to distinguish the categories of starch. Recent studies suggest resistant starch is rather beneficial to your health.
Hindustan Times: Starch in bananas, potatoes, grains beneficial for health, confirms study
Resistant starch is contained in banana, potato, legumes, and even in grains. It is hardly digested in your intestine. Thus, it works as the same as dietary fibers. Several studies showed the fact that taking resistant starch reduces your appetite, to protect you from overeating. At the same time, postprandial glycemic response after taking resistant starch is regulated at an acceptable level, resulting in the decreased risk of diabetic diseases.
Nutrition Bulletin: Health effects of resistant starch
This article above is a non-systematic review. Thus, its evidence level is not enough to reliable. I cold not find any research on systematic reviews using meta- analysis of clinical trials in this area. It is difficult to conduct an intervention study with human participants to identify the effect of a particular substance on the health.
Nonetheless, I think this hypothesis is likely to be right. Resistant starch is considerably beneficial, or at least less harmful than white sugar. In Japan, some people take bananas for the purpose to maintaining their body weight. And potatoes are recognized to improve your laxation.
Of course, overtaking them is no good. Balance diet is essential for the healthy life.