What Men in Their 30s Should Focus On: It's Not the 'Beer Belly,' But 'Leg Thinning'—Tanita Data Reveals the Surprising Truth Behind Body Shape Changes

Haruyama Trading Co., Ltd. (Headquarters: Okayama City, Okayama Prefecture; Representative Director, Chairman and President: Masafumi Haruyama; hereinafter 'Haruyama'), which supports the health of business professionals, has announced that cumulative sales of the 'i-Suit SUPPORTED BY TANITA,' developed in collaboration with Tanita Corporation (Headquarters: Itabashi-ku, Tokyo; President: Chisato Tanida; hereinafter 'Tanita'), have exceeded 50,000 units (as of January 2026)*1. Taking this opportunity, the two companies combined their 'suit size data' and 'body composition statistical data' to analyze the trends in body shape changes that business professionals face with aging, as well as the underlying bodily cycles. The analysis highlighted that behind the abdominal changes that concern male business professionals in their 20s to 40s lies a change in 'leg muscle mass.' To maintain body shape and health, it is crucial to increase daily activity levels and engage in training while being mindful of maintaining lower-limb muscle mass. Ahead of the spring health checkup season, we will introduce the identified trends in body shape changes and bodily cycles, along with methods for efficient health improvement and the apparel that supports them.

[Trends and Concerns in Body Shape Changes] The 'Beer Belly' and Changes in Fat Distribution with Age Suit waistlines becoming tight—this is a concern faced by many male business professionals as they age. Looking at Haruyama's suit purchase data, slim 'Y-type' and 'A-type' suits are mainstream for those in their teens and 20s, but there is a notable shift toward 'AB-type' suits with more room in the waist starting in the 30s (Figure 1). Supporting this concern and the change in suit types, Tanita's data also shows a trend of a sharp increase in BMI from the 20s to the 30s (Figure 2).

Figure 1: Composition of Men's Suit Size Purchases (Source: Haruyama)*2

Figure 2: Changes in Male BMI Starting from the 20s (Source: Tanita)*3

Furthermore, when looking at changes in fat percentage by body part (legs, trunk, and arms) across age groups, up until the 20s, all parts...