Uneven bars: manufacturers of all sorts belly up to the bar category with a slew of new nutrition and snack products, to varying degrees of success.

Nutrition and snack bars, by their nature, are loaded with all sorts of ingredients. That pretty much mirrors the category as a whole. In fact, supermarkets, mass merchandisers, convenience stores, health food stores, fitness shops and other retail outlets are packed with an ever-increasing

Indeed, just visit a grocery store and see how everyone who's anyone wants to get into this polymorphous category. In the nutrition bar section, often located near the health and pharmacy aisles, the shelves teem with products made by companies ranging from vitamin manufacturers and mom-and-pop startup operations to candy conglomerates, such as The Hershey Co.

A few aisles over, in the snack and cereal sections, scores of other bar products beckon shoppers, again reflecting a diverse group of producers that spans peanut butter companies, cereal giants and grassroots health-food organizations. In many outlets, energy bars and snack bars also are available in impulse-buy areas near the checkout line. And that's just in the supermarket channel.

Recent market research underscores the fact that in terms of sales, this segment isn't easily pinned down. According to Chicago-based Information Resources Inc. (IRI), while the overall bar category grew 3.3% last year to reach the $1.82 billion mark, brands within each subcategory experienced a wide swing in sales.

Within the breakfast/cereal group, for instance, one new branded product jumped 1,433.7% in sales, and another climbed nearly 244%, while three other top brands lost a good percentage in sales during 2005. In the granola bar segment, six of the top 10 brands got a boost in sales, while four recorded a decline.

IRI also reports that sales in the nutritional/intrinsic health segment dropped off 11%, although six of the top 10 brands experienced an uptick in sales, ranging from 0.9% to 990.8%. Similar splits in sales are reflected in data for rice snack squares and "other" snack/granola bars, reflecting these dynamic categories' fluid state of affairs.

Behind the numbers, why have so many disparate manufacturers opted to become competitive in the bar category, and why have they encountered varying degrees of success? Maybe this mature category has kept growing because it constantly reinvents itself to be on-trend.