Animal tests expose diet products as sham

Animal tests have shown that nine types of diet products do not generate the slimming effects advertised by their manufacturers, officials at a national health laboratory said Tuesday, without revealing the products’ names.

The Health, Labor and Welfare Ministry ordered the tests by the National Institute of Health and Nutrition. It plans to urge the firms to remedy the situation if it determines that they violated the health promotion law, which bans false advertising.

It is the first time that the actual effects of these products have been investigated. In the past, the health ministry simply warned the public, based on its survey of published documentation, that the scientific grounds for the touted effects of some diet products were unclear.

Ministry officials said the move is an attempt to provide consumers with objective information amid a slew of dietary products, many of which tout dramatic results, now available on the market.

Manufacturers of the products claim in their ads that using them will allow fat to be excreted together with the stool. The products are said to be able to congeal fat during the digestive process so that it is not absorbed by the body.

In the experiments, the institute mixed nine types of diet products with the feed of mice and allowed the mice to eat the feed for three weeks.

When they studied a control group of mice, which did not eat the feed, they found they excreted slightly more fat but did not exhibit a major difference in weight gain or loss, as more than 98 percent of the fat they had consumed had been absorbed by their bodies.

The institute concluded that regular consumption of any of the products will not generate slimming effects as advertised.

The results of the experiments will be announced at a meeting of the Japanese Society of Clinical Nutrition that opens Oct. 1 in Osaka.