You’ve probably heard it a million times; being fit comes down to 80% nutrition and 20% exercise. It’s basically a wellness commandment but talk to dieticians or doctors and you will get a VERY different opinion.
Now this isn’t talking about the other 80/20 rule of eat clean 80% of the time. (Although that is a separate topic and it definitely isn’t as black and white as it seems.) No, this is going to the source of what many fitness professionals will tell clients to do in order to get fit and healthy. Unfortunately…it’s B.S.
I say some PTs here because most nutritionists and dieticians will not give this advice. Some PTs, on the other hand, are simply recycling the “law” that has been announced decades ago without really looking at how the science has changed or recognising just how different each person is. They don’t mean to steer you off course because most of them believe in this rule themselves. As a PT myself, I certainly did before I got my nutrition certification.
The 80/20 rule is helpful without being overwhelming; calorie and macro counting can quickly lead to obsession and both are NOT sustainable strategies in the long run. A simple 80/20 split, on the other hand, is easy to do, doesn’t require much tracking and is definitely preferable to no guidelines at all. This is also why some PTs will tell you to follow it. From this point of view, it makes sense.
You may find that this split just doesn’t work for you. Or maybe it did for a while and then it stopped. You can’t figure it out. Why does Maria or Amy (I’m making up names here hehe) live this rule and stay super fit but you do EXACTLY the same and struggle?
No you’re not crazy and nothing is wrong with your body but a LOT is wrong with this rule. Here's why....
Everyone’s body is different. Not only that, everyone’s body is different at different times. You on birth control, you during your period, you during a time of stress, these are all different states that your body goes through and it does NOT operate the same across all of them. Beyond that, your body could function entirely differently from someone of the same race, age, height, weight and activity level merely because of genetics, sleep, hormones and other environmental factors. It’s impossible to say that one set split works for all the people all the time.
This rule seems to originate from two places. The first, is from the Pareto Principle, which is a 100 year plus economic discovery that 80% of effects come from 20% of causes. This principle has become the basis for everything from how the world works to productivity and sales advice. The second origination of this rule comes from the observation that your body will, on average, burn about 20% of the calories you consume through exercise.
But does the science back it up?
When it comes to energy expenditure or how your body uses energy (aka calories) there are three main parts to it:
If we break this down, it’s generally the consensus that 60% to 80% of your energy is consumed by resting needs (measured by basal metabolic rate), approximately 10% is for digestion and 20% to 30% is for physical activity like workouts. Do you see the issue?
Let’s look at those figures again. What determines whether you burn 60% vs. 80% at rest and 20% or 30% for workouts?
It's not a simple split because many factors determine your energy needs and expenditure, among them are:
It means that you may actually have to eat healthier than other people in order to get the results you want or maybe you can train less. Maybe your split is more like 90% nutrition and 10% exercise. This can be particularly true for women with a genetic tendency towards wider hips and thighs. I’m one of them! We soak up fat much more quickly and than someone who is naturally more lean; that leaner person might only require 70% healthy eating and 30% exercise because their body burns energy differently. This is why you cannot rely on the 80/20 rule. If it’s worked for you? Great! That means the split is true for you.
However, if you’ve been doing everything right — eating well most the time and exercising— but not getting the results you want, then you might want to play with the equation. Try eating healthier. Try doing more exercise or less. Find the balance that works for you.
I can tell you that after having worked with hundreds of clients of all ages, sizes and ability levels, none of them were exactly the same. Some needed to train more, some needed to train less. Some could eat more unhealthy foods. Some had to eat less. For me personally, I’m more of a 70% healthy eating and 30% exercise kind of girl but this changes based on stress, sleep, hormones, etc.
The key is to stay attuned to your body because you know what?
The golden rule in fitness that holds true for EVERYONE is this…focus on what your body needs not what the numbers say.
Get a 360 Wellness Assessment. This is where you’ll talk over your nutrition, body composition, fitness history and eating habits. With this complete information, a Wellness Profile can be made and you can stop feeling frustrated at the lack of progress!
Want to have a peek at how it works? like this pop-up to appear on the page. Book a PT Wellness Chat! If you’re ready to start seeing a change in your body and the way you feel, come grab one of my 15 minute monthly spots. I only do a few of these each month so if you’re committed to change and finally getting in results, book it in asap.
Let’s figure out what you can do NOW to go further with your fitness, nutrition and mindset.