The market, he said, got more impetus after the COVID-19 pandemic outbreak as more and more people began to pay attention to appearance, weight and health management.

Market consultancy iiMedia Research said that another major consumer group in the meal replacement market is mainly women who want to lose weight and keep fit. They usually choose meal replacement products, including chicken breast and protein bars.

According to a research report from Meituan, a Chinese integrated platform for delivery services and shared mobility solutions, 70 percent of consumers of meal-replacement products are female, and those born between the 1980s and 1990s account for 40 percent of all consumption.

Li Hongcan, 26, a product manager based in Hangzhou, Zhejiang province, said that as a bodybuilder, she drinks a bottle of probiotic yogurt every two days and munches on a muesli energy bar during her work break.

"For me, eating a protein bar is like enjoying snacks. It packs in the right amount of calories and nutrients, which is an ideal way for me to keep in shape," she said.

Consumption of such groups can be huge. For instance, in 2020, the latest year for which data are available, there were 70.29 million gym members in China, with a penetration rate of 4.87 percent. Penetration rate is a measure of how much a product or service is being used by consumers compared to the total estimated market.

As meal replacement products continue to gain popularity, more startups as well as traditional food giants are jumping on the health food bandwagon. China Mengniu Dairy Co, for instance, introduced a milk variety that can help slow-burn body fat.

Companies are planning various innovations to attract more consumers. For instance, Smeal Biotechnology Co Ltd, founded in 2020 in Shanghai, received instant consumer backing on Nov 11－Singles Day, a popular online-and-offline shopping festival in China. It sold 1 million bottles of its flagship smoothie powders on Tmall, an online marketplace of Alibaba Group.

Unlike other smoothie meal replacement products, the Shanghai-based company mainly offers powders, enabling consumers to add water to make meal-replacement beverages, just like bartenders.

In addition, the company beefed up its efforts to diversify flavors so as to make meal-replacement products tastier.

It boasts more than 10 flavors across different products, including matcha, chocolate and black sesame, which is embedded with some Chinese characteristics and is said to be popular among Chinese consumers.

"For new categories like meal replacements, it is hard to retain consumers. The only thing that can keep consumers loyal is innovation in products, including formulas, nutrition and taste," said Cao Peng, founder of Smeal.

While some brands have hit pay dirt, others have hit road bumps. Element Fresh, a Shanghai-based chain that serves healthy foods, including salad and some meal-replacement foods, filed for bankruptcy protection in December.

Industry insiders said the sector has not yet formed mature and unified standards, and there is a lack of scientific and reasonable guidance on meal replacement products.

"Not all meal replacements advertised in the market can completely replace normal meals. And many consumers don't know how to eat such products in a proper way," said Zhang Tian, a nutritionist at the Aviation General Hospital of China Medical University, in a media interview.

Chen Momo, vice-president of VisionPlus Capital, said millennials have options other than meal replacements to lose weight and get fitter. For example, they can choose healthier lifestyles, like cooking their own meals and working out. Such an approach can also produce benefits that meal replacement products offer, Chen said.