If those jeans you got as a gift this holiday season don’t fit because of the all the food you devoured in the last few weeks, you might be tempted to buy one of those exercise devices advertised on TV. But some of these products aren’t worth the price — or effort.

Getting a jump on the post-holidays fitness push, our slimmer cousins at Consumer Reports recently put three such products — Jay Glazer’s Perfect Punch, the Nautilus CoreBody Reformer, and the Rhythm Rocker — through the wringer to see if any of them provide a return on investment.

Jay Glazer’s Perfect Punch
This is the system sold by no-necked NFL reporter and UFC host Jay Glazer for $30 plus shipping and handling. It uses resistance bands to supposedly simulate a mixed martial arts workout and includes a workout plan and DVD.

But when Consumer Reports’ fitness expert did an energy expenditure test on the Perfect Punch, he found that its 16-minute workout burns about the same amount of calories as jogging on the treadmill at 4.5 mph for 16 minutes. And if you follow along with the included DVD, be aware that the instruction isn’t only repetitive, but it doesn’t provide adequate warm-up or cool-down. The expert also noted that the DVD lacks reminders to users about maintaining good form throughout the workout.

As for claims that Perfect Punch will improve one’s punching ability, Consumer Reports testers with longer reaches actually found that their punching form had been compromised and that the resistance bands were sometimes irritating.

Rhythm Rocker

Do you want the benefit of dancing without actually having to stand up? That’s what the $99 Rhythm Rocker claims to offer.

And as you might expect from a “dance” workout that doesn’t require you to leave your seat, Consumer Reports’ fitness expert found that the Rocker only burns calories at the same rate as walking at 2 mph on the treadmill. He also cautions that, in spite of claims made by the manufacturer, that the Rocker is not good for users with lower-back problems as it provides no lumbar support.

One tester describes the device as “an exercise for people that don’t want to exercise that much.”

As for the 7-day diet included with the Rocker, CR found that the program is so strict that the user could possibly lose the advertised 7 pounds in a week, but there is no maintenance program included, so it’s a pointless endeavor.

Consumer Reports bottom line: Save your $99 and just dance.

Nautilus CoreBody Reformer
Here is a device and exercise program, targeted mainly at women, that claims to combine yoga, Pilates and dance.

A number of Consumer Reports testers found that the Reformer actually offered a worthwhile workout, though the $250 price tag can be hard to overlook. And some testers found it overly difficult to balance on the Reformer.

So if the cost is too high for you to consider, CR suggests the less-expensive option of working out using yoga and Pilates DVDs.

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