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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!

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Esti says:

Hi Grame, I don’t see how this study shows that the cardio wasn’t effective.  If diet wasn’t monitored, couldn’t it be that the exercise group just consumed more calories due to increased energy expenditure and thus experienced no weight loss????

Anonymous says:

Great observation: it is most definitely possible (and likely) that the exercising group consumed more calories, leading to no change in weight.

Which is essentially the observation that the majority of published exercise studies have found: trying to lose weight by simply increasing exercise alone very rarely works, because it is typically accompanied by an increase in appetite.

Fact of the matter: intentionally weight loss almost always requires dedication and vigilance to the diet side of the equation.

Without an intentional capping of “calories in”, in today’s society with essentially unlimited and low-cost access to calories, weight-loss efforts consisting of mostly exercise (accompanied by the increase in appetite) tend to always fail in the long-run.

So successful weight loss (for most people) requires some exercise + intentional diet control (ideally focusing on a calorie-controlled diet consisting primarily of nutrient dense foods).

Mereniecrosby says:

Graeme I lost 40 pounds walking about an hour a day and eating roughly 1500 calories a day.  2 years later I am still at this point, now I run 5 k 3 x a week and spin one hour 2 x a week. I do at least an hour of exercise 5 days.  Plus I do a body pump class twice a week with lots of squats, and lots of weights – What can I do to get from 160 pounds to 140 pounds.  My body is perfectly happy at this weight and has adjusted totally to this.  Why is my body at such a plateau, and should I just go back to the walking? 

Rosi Roo says:

This is a great article and makes a lot of sense. Thanks!

Scott Mundy says:

Graeme, I recently had this conversation with a friend and trying to see things from their perspective I came to these conclusions..what do you think?

I find more often that not women (and men) who perform this type of activity do so because it is easy to do. Suggesting a more effective alternative with a higher RPE would greatly reduce their adherence to an exercise program. I find that this attitude is quite common. They would rather not exercise if they need to work hard. As you know any effective training requires a person to go beyond their comfort zone which is why I believe steady state cardiovascular exercise is so common. So with that said do you think that this type of activity could almost act as an influence (gateway drug) to future adherence to better training protocols? Better to do something that nothing at all!? I rather see someone enjoy steady state exercise as an introduction to physical activity in their lives then give them something that would be more effective for their results but less effective for their sustainability.

Anonymous says:


I agree with you 100%. When starting to work with anyone who has yet to establish good exercise or diet habits the key objective is always to get them doing “something regularly”.

Although steady state cardio isn’t the best tool for fat loss, it’s better than sitting on the couch. So if that’s the only thing someone can be “regular” with, then so be it. Once that individual has made daily exercise part of their regular routine, then start progressing them towards more effective approaches for their goals.

Same thing applies to dieting. Although commercial protein bars aren’t my idea of optimal health, they are a much better option (and an easier behavioural sell than an bags of celery) when trying to wean someone off chocolate bars. So start with that and over time try to get someone to adopt even healthier habits.

The idea I give many of my clients is that “don’t worry about being perfect. Just try and make a better decision today than you did yesterday”. As long as they commit to this ideal, they are better able to understand how they need to progress over time.

STUCK ON A PLATEAU?  Optimize Your Diet Today.