TORONTO - Beginning today, new rules instituted by Health Canada will limit the amount of caffeine per can or single-serving energy drink bottle to 180 mg, about the same as an 8-ounce coffee, the Toronto Star reports.

The new rule will force energy drink makers to reformulate 28 drinks that previously populated the shelves of Canadian retailers.

Additionally, popular drinks marketed by Monster, Rockstar, and Full Throttle, which were previously categories as "natural health products," are now being reclassified as "food," thus coming under the new caffeine cap.

"When setting the 180 mg limit, we looked for a level that would not represent a risk, based on expected consumption patterns for these drinks," said Health Canada spokesman Sean Upton. Large, resealable bottles are also being capped at 400 mg of caffeine per liter.

Additionally, for the next five years, energy drink makers must report annual data on sales, consumption and health incidents.

Health Canada said it will assess the data before determining whether further regulations are merited. "We consider there to be (information) gaps right now, as to how these products are actually being used," said William Yan, a director in Health Canada??s bureau of nutritional sciences.

As of today, only reformulated versions can be produced, though stores don??t have to pull drinks already in stock.