Current trends on the Japanese food market include premium chocolate besides other sweets as well as health foods. There are many European brands already successful in Japan, such as Valrhona, Haagen Dasz or Haribo, many other to name here. European manufacturers of vitamin products, natural foods and special functional foods do also increasingly well in Japan.
It may be true that entering the Japanese market at first is a challenge as quality expectations are high and customer service demanding - but once in the market established, foreign products do generally well and enjoy long-term sales with increasing brand power among Japanese consumers. Western quality products are overall very popular. Also, Japanese people spend a bigger part of their monthly budget on foods (15-17% in average - compared to 9-12% for Europeans and just 5-7% of US-Americans), partly caused by the high rate of food imports to Japan.