Ladies, Cardio Sucks For Weight Loss

A few weeks ago, I gave a talk entitled “Skinny Genes: Why Females Fail with Steady State Cardio” that covered some of the major reasons why using steady state aerobic physical activity as a primary fat loss tool rarely works, for females.

Now before anyone sends me an angry email saying “but my friend lost 40 lbs doing nothing but the elliptical… blah, blah, blah”, I’d like to remind you that our society is home to a few females with fortunate genetics who’ll actually respond to aerobic exercise, but but by and large trying to manage body fat through excessive hours of cardio is moronic.

One of the studies that highlights this ineffectiveness of cardio as a weight loss tool is the Midwest Exercise Trial, a 16-month exercise study. In this particular study, researchers studied four groups of individuals: 2 exercise groups (one male, one female) and 2 control groups (also one male and one female).

The exercise groups were asked to burn at least 2000 kcal/week by way of steady state physical activity (intensity was tracked and participants worked out at about 77-80% of their max HR or around 65% of their max VO2… so a moderate intensity). The control groups pretty much just sat around doing nothing. Lucky them.

For anyone wondering what 2000 kcal worth of energy might look like, an average sized human will burn ~100-125 kcal jogging for 10 minutes. So for someone training 5x week, 2000 kcal amounts to spending ~30-40 minutes in the gym during each of those five sessions.

One important thing to note was that there was no actual diet intervention in this study, it was strictly a study focused on the ability of aerobic exercise to produce weight loss.

The really neat thing about this particular study was that these exercise groups were followed for 16 months. As loyal readers will know, I’m not a huge fan of short-exercise or diet studies since it’s not exactly reflective of what people will continue doing in the real world. However, 16 months gives us a nice amount of time to see what actually happens when people do all this exercise.

Well at the end of the 16 months, some really interesting data emerged.

As it turns out, doing steady state cardio for almost a year and a half is a reasonably effective way to cause weight loss in young males. But let’s be honest, young males (as a group) are the most responsive members of society to any exercise or diet intervention, so let’s not pat ourselves on the back too much for this result.

N.B. For anyone wondering, almost all the weight loss for these males (96%) came from fat, so this exercise intervention clearly was effective.

Far more interesting was the fact that despite expending 2000+ kcal of energy at the gym each week for 16 months, young females lost absolutely zero weight. Think about that for one minute, these young ladies spent over 213 hours in structured physical activity over a period of 16 months and they didn’t lose a single lbs… talk about depressing!

N.B Now to be fair, these young ladies didn’t gain any weight (like what happened to the control group) but still, you don’t spend hours at the gym hoping to see no visible results in the mirror or on the scale.

So what gives?

Why does steady state cardio work for males and prove to be absolutely useless for females? Ladies, you can blame your biology.

Without going into all they physiology for why, just appreciate that the following course of events seems to happen in females:

Whenever females start doing hours and hours of cardio, their resting metabolism (or possibly even their appetite) will adjust to make sure their precious levels of body fat can be maintained. While this was an awesome survival mechanism throughout evolutionary history, it’s pretty damn frustrating in today’s day and age when people want to be lean for vanity reasons.

Now this doesn’t mean that steady state cardio exercise will never help females get lean, because it can. But unless a female is doing a minimum of 3-4 hours of intense physical activity a week, I never recommend they do steady state cardio (if fat loss is a goal).

In fact, I’d have to say that until females master the following 4 domains, cardio won’t make much difference to their physiques at all:

  1. Eating the right diet for your goals/genetics
  2. Increasing lean mass through resistance training
  3. Disrupting homeostasis through interval training
  4. Improving recovery through sleep and stress reduction.

So for all those ladies out there trying to remake their physique, stop slogging away for hours in the gym with little to no noticeable benefits. Instead spend the bulk of your time at the gym resistance training, but pair it with a rock solid diet plan.

Till next time, train hard and eat clean!