The 4-Hour Body Workout: Can You Gain 34 Pounds of Muscle in 28 Days?

four hour body reviewSeems like every time I check my e-mail, somebody somewhere wants to know what I think about the 4-Hour Body workout found in The 4-Hour Body, the latest book by Timothy Ferriss.

No matter what you might think of Ferriss, he knows how to sell stuff. I haven’t seen such a slick marketing job since Bill Phillips launched Body-for-LIFE in the late 1990’s.

I haven’t read the entire book, so I can’t comment on everything that’s in there. But I have seen a few sample chapters. And the one that caught my eye was called From Geek to Freak: How to Gain 34 Pounds in 28 Days.

In it, Ferriss says that he followed a training routine based on the so-called Colorado Experiment. Despite just two 30-minute workouts per week, for a total of 4 hours of gym time, Tim claims that he gained 34 pounds of muscle in 28 days while also losing 3 pounds of fat.

What was the Colorado Experiment? And is it really possible to gain 34 pounds of muscle in 28 days using the 4-Hour Body workout?

The so-called Colorado Experiment wasn’t really an experiment. It was a giant marketing exercise by Arthur Jones, the inventor of the Nautilus range of exercise machines.

Like Phillips and Ferriss, Jones was a marketing genius. The fact people are still talking about the Colorado Experiment 30 years on shows what a thorough job he did.

The “experiment” ran for a period of 28 days back in May 1973. In it, Casey Viator, who was the youngest ever winner of the AAU Mr. America contest in 1971, allegedly gained 63.21 pounds of muscle and lost 17.93 pounds of fat. And he did it all using only Nautilus equipment.

But according to Bill Starr, the guy who popularized the 5 x 5 training routines that are so popular at the moment, the whole thing was “a hoax.”

“One of Arthur’s greatest marketing schemes revolved around the amazing progress that Casey Viator had made in just a month while using Nautilus machines exclusively,” says Starr.

“It was called the Colorado Experiment and helped Jones move a lot of equipment. What the public didn’t know was that Casey was taking steroids the whole time without telling Arthur and he was also sneaking out to a local YMCA to train with some real weights. I know this because Casey told me so.”

Prior to taking part in the Colorado Experiment, Viator had lost over 30 pounds in weight after he almost died from an allergic reaction to an anti-tetanus injection.

So some of his gains were due to the fact that he was re-building lost muscle, which is faster than gaining it in the first place.

Like many competitive bodybuilders, Casey was also on steroids at the time. Even so, his results — an average muscle mass increase of 4.51 pounds per workout — border on the miraculous.

Which brings me on to the subject of Timothy Ferriss and The 4-Hour Body workout.

Here’s the workout that, along with a diet providing 5,000-8,000 calories per day, Tim claims is responsible for his remarkable results.

Pullover + Yates’s Bent Row 1 set x 8-12 repetitions
Shoulder-Width Leg Press 1 set x 8-12 repetitions
Pec Deck + Weighted Dips 1 set x 8-12 repetitions
Leg Curl 1 set x 8-12 repetitions
Reverse Thick-Bar Curl 1 set x 8-12 repetitions
Seated Calf Raise 1 set x 8-12 repetitions
Manual Neck Resistance 1 set x 8-12 repetitions
Machine Crunch 1 set x 8-12 repetitions

Each set was taken to failure (i.e., reaching the point where you can no longer move the weight). He also performed every repetition with a 5/5 cadence (five seconds up, five seconds down). The “+” indicates the use of a superset.

There are some elements of Tim’s 4-Hour Body workout that I like. Training a muscle group two or three times a week, for example, generally works better than training it once a week.

But the other training methods Tim employed (slow lifting speeds and single rather than multiple sets) have not been shown to produce the kind of dramatic gains in size or strength that Ferriss is claiming.

Is it even possible to gain 34 pounds of muscle in 28 days?

Well, that really depends on how you define the term “muscle.”

Tim has previously described how he arrived at a Sanshou (Chinese kickboxing) contest weighing 187 pounds, dropped 22 pounds (down to 165) in time to be weighed in, before adding 28 pounds to compete the next morning at 193 pounds.

In other words, Ferriss was able to gain 28 pounds of “fat-free mass” in just 12 hours. This was done by manipulating fluid and glycogen levels in his body with the use of water, glycerol, carbohydrate and creatine.

Something else to consider is the fact that Ferriss was re-building some of the muscle he’d lost during tango training in Buenos Aires. When he started his experiment, Ferris weighed just 146 pounds, which is around 30 pounds lighter than his regular weight.

Why does this matter? A phenomenon known as “muscle memory” means that re-building lost muscle is a lot easier than gaining it in the first place.

When you take all of this into account, a 34-pound gain over 28 days doesn’t seem quite so unbelievable. But if you leave muscle memory and fluid manipulation OUT of the picture, the idea that you can gain 34 pounds of muscle in 28 days is total BS.

Even in a study where they used untrained guys in their late teens and early twenties, who have a relatively easy time building muscle, gains in lean mass averaged only 12 pounds over a 10-week period.

The vast majority of people would be doing remarkably well to gain 34 pounds of muscle in a year, let alone 28 days.


If you're fed up spending hours in the gym with nothing to show for it, then check out The Muscle Building Cheat Sheet.

It's a step-by-step, straight-to-the-point PDF that tells you exactly how to go about building muscle. To download a copy, please click or tap here.

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Christian FinnChristian Finn holds a master's degree with distinction in exercise science, is a former personal trainer and has been featured on BBC TV and radio, as well as in Men's Health, Men's Fitness, Fit Pro, Zest, and Perfect Body magazine.