Bannatyne Fitness, which operates 59 clubs, saw pre-tax profits fall to £7.8 million in 2011 from £12m a year earlier.
But the company also suffered a £24m impairment of assets, thought to relate to the slump in commercial property prices, which saw the group make a bottom-line loss of £16.2m. Turnover edged up to £89.1m from £89.06m. Net assets fell to £37.3m from £51.3m.
In their report, directors said they were “disappointed with the results” and said they expected “the industry to remain tough”.
The group employed 2,567 staff during the year, marginally down on the 2010 figure. Borrowings fell from £148.5m to £138.6m.
Although no charitable donations were made by the company in 2011, the Bannatyne Charitable Trust donated £315,583 to good causes.
Last month, it was revealed that Clydebank-born Bannatyne was looking to blaze a trail in the world of fashion.
A spokesman for the tycoon said a range of clothing had been designed after members of his gyms had expressed a desire for clothes that were “practical, fashionable and affordable”.
Bannatyne, who worked as a welder, sailor, hospital porter and ice-cream van salesman before setting up his gyms empire, is estimated to have a fortune of about £430m.