The apple cider vinegar diet is regaining popularity. Apple cider vinegar is crafted through the fermentation of cider (apple cider). Initially, when apple juice undergoes fermentation with yeast, alcohol is generated. Subsequently, this alcohol is fermented with acetic acid bacteria to yield vinegar.

Apple cider vinegar diets experienced a surge in popularity during the 2000s. In 2005, a Swedish study demonstrated that consuming vinegar with bread led to a slower rise in blood sugar and insulin levels after a meal. A 2009 Japanese study involving 155 adult participants revealed that those who consumed 15 or 30 ml of apple cider vinegar daily for 12 weeks lost 1 to 2 kg of weight compared to a placebo group. More recently, in March this year, a Lebanese study reported even more significant findings. Participants who consumed apple cider vinegar lost 6 to 8 kg in contrast to those who consumed a lactic acid solution, which acted as a placebo.

When results seem too remarkable to be true, skepticism is warranted. In the case of the Lebanese study, a smaller dose of vinegar (5, 10, or 15 ml) was administered compared to the Japanese study. Vinegar carries a distinct nasal odor, whereas lactic acid solution emits a milder scent, potentially enabling participants to discern which substance they received. Furthermore, the age range of participants was relatively young in the Lebanese study, spanning from 12 to 25 years old, with no dietary or exercise restrictions imposed. It becomes challenging to exclude the possibility that factors beyond the vinegar intake could have influenced the observed differences in weight loss. Consequently, many experts have raised doubts about the reliability of the findings. Putting faith in the Lebanese study and committing to apple cider vinegar consumption for three months is unlikely to result in an 8-kilo weight loss as suggested.

Indeed, there may be some beneficial effects associated with apple cider vinegar, primarily stemming from the vinegar itself. When paired with starchy foods, vinegar has shown potential in regulating blood sugar levels. This effect could be attributed to acetic acid, the primary component of vinegar, which may impede the activity of starch-digesting enzymes or decelerate the movement of food from the stomach to the intestines. For optimal efficacy, vinegar should be consumed shortly before a meal, ensuring its presence in the stomach prior to the arrival of starchy foods. However, it's essential to refrain from consuming vinegar undiluted. Vinegar's acidity can damage tooth enamel, and ingesting it improperly poses risks of aspiration into the airways, which can be hazardous.

In fact, consuming 15 ml of vinegar diluted in a glass of water before a meal, particularly alongside bread or rice, can induce a sensation of fullness that lasts longer. Conversely, it may also lead to discomfort from indigestion. Consequently, you may find yourself eating less and experiencing some weight loss. Nevertheless, it's crucial to recognize that this isn't a miraculous solution. The cyclical resurgence of the apple cider vinegar diet, falling in and out of fashion, suggests its limited effectiveness. Rather than adhering to transient fad diets, it's prudent to establish sustainable eating habits that you can maintain throughout your life.

Jeong Jae-hoon is a food writer and pharmacist. He covers a variety of subjects, including trends in food, wellness and medications. This column was originally published in Korean in Joongang Ilbo on Arpil 11, 2024. – Ed.