Dear Cassey: What’s the deal with the 80/20 rule?

Dear Cassey

I’ve been hearing a lot about this 80% diet 20% exercise. I was wondering if this is true, or is this just a myth? If so does this even work? And how do I do the whole 80/20 thing?

Thanks in advance!

Just Wondering

Dear Just Wondering,

Ahhhhhh the 80/20 rule! First, did you know that this is actually based on something called the Pareto Principle? Basically, it came from an economist who said “80 percent of consequences come from 20 percent of causes.” And if you really think about it, it actually works for a lot of situations! INTERESTING, right?!

Okay, but is the 80/20 rule legit for fitness, losing weight, etc. orrrr just a myth?

I like to look at it as a tool, or a guideline. There are two ways you can actually use the 80/20 mindset to get yourself from point A to point B when it comes to your fitness goals.

First is the specific idea you’re asking about: 80 percent diet, 20 percent exercise.

IDK about the specific numbers being necessary here, but the takeaway for me is that you have to do BOTH. If you want to lose weight, exercise alone isn’t enough to get a consistent calorie deficit unless you’re pushing really hard every day. And that’s not really ideal. On the flip side, trying to get a solid calorie deficit over a consistent period of time on diet alone would be difficult too. It really does take both.

The exact breakdown of 80/20 in this scenario isn’t an exact science. It just comes down to opportunity. We eat a lot more often than we exercise, right? I found a really interesting article that did the math:

“Let’s take percentages out of the equation for now and apply some logic to exercise and nutrition. The normal exerciser may perform three to four weight training sessions and three to four cardio workouts per week, totaling eight sessions per week.

This gives eight opportunities to make a positive change in your body through exercise. That same person eats three healthy meals per day. If knowledgeable in the value of meal spacing, these people may eat five to six times per day. Quick math shows 21 to 35 chances per week to directly and positively impact fat burning and muscle building goals through nutrition.”

So, that’s 8 chances for exercise and 21-35 chances for food per week. If we do the math, that DOES come out to be about 80 percent nutrition and 20 percent exercise! But like I said, not an exact science. Just a way of showing that nutrition is super important!

The other way the 80/20 rule is used is to keep a diet more sustainable.

You stick to eating healthy 80 percent of the time, but relax and indulge a little the other 20 percent of the time. There have been studies that show this method works for more people than other methods! But like with everything, I think it realllllly depends on the person. For some, it’s a more approachable and sustainable method than trying to count calories or macros. It’s flexible and leaves room for all foods. BUT for some people, it can quickly turn negative. It’s easy to over restrict and punish yourself on “clean” eating days. And it’s just as easy to overindulge on your more relaxed days. So even though this guideline of 80/20 has its perks, a healthy lifestyle will always come down to moderation.

So that’s where I’ll leave you, and hopefully, it gave you some guidance!

The 80/20 rule isn’t exactly a myth, but it’s also not a perfect solution for everyone.

The best way to incorporate this principle into your own lifestyle is to eat whole, nutritious foods MOST of the time, while including your favorite foods in moderation too, even if they’re not “healthy.” And of course, find a way to move your body that brings you joy!

PS – If you have a burning question you want to ask me, leave your questions below! I may answer it in an upcoming Dear Cassey post!

26 thoughts on “Dear Cassey: What’s the deal with the 80/20 rule?”

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  1. Madeline says:

    80/ 20 rule is very popular amongst weight watchers.

  2. Tired and exhausted says:

    Dear Cassey,
    I started doing the hot girl summer challenge but I’m currently working on my internship, on my dissertation and I’m in a relationship. Right now I feel tired, exhausted, drained out, but I also feel guilty for missing 4 workout days. On top of that, my diet is going back to the old days – cookies, bread, no water and eating when I’m not hungry.
    How can I overcome this feelings and be active again?

  3. Recovering says:

    Dear Cassey,
    I was doing the Hot Girl Summer Sculpt, and doing super great. My body felt amazing, I loved the way it looked, I loved working out, etc. But yesterday, I got surgery to remove three wisdom teeth and, consequently, I have to stay in bed for approximately three days and eat small snacks every few hours because of medicine.

    What can I do to not lose my progress, nor gain weight during this period of recovery?

    1. blogilates says:

      Take it easy – surgery is no joke! Walk when you can and just try to stay moving (with light movement). Once you’re feeling better, hop back on and you’ll be good to go!

  4. Stuck in the Middle says:

    Dear Cassey,

    I find it hard to keep a healthy diet because I love food so much. I like to eat a lot and I find it hard to stop. I tried meal prepping but usually I end up throwing out half the meals because I hate the taste of leftovers. Unfortunately I’m not always free to cook and I don’t always know what to eat so I eat the most accessible thing which isn’t always the healthiest option. Please help, I’m feeling trapped by food.

    Stuck in the Middle

  5. Tired and Confused says:

    Dear Cassey,
    I hear a lot of people talk about having so much energy and happiness when working out a lot and eating healthy. But I personally find myself drained, exhausted, constantly craving sweets, and less happy. I’m not sure what to do because I want to be healthy but I just don’t feel mentally happy when I try. What should I do?

    Tired and Confused

    1. Tired and exhausted says:

      Hey. Tired and exhausted here.
      I understand what are your doubts and struggles. First, don’t compare your feelings with other people’s feelings and life. Don’t put your self worth on society’s expectations. Every life is different, therefore it shouldn’t be comparable. Second, you should workout because you want to and makes you feel good, confident about yourself and your body. If you workout because of these things and still manage to lose weight (for example) that’s even better. Third, you should find workouts that you connect and like (for me I love pilates but I also love HIT workouts and Tabata). Find your type of workout, suitable for your body type. You should eat healthy, nutritious foods but you can eat your favourite foods once in while. The key is balance. And of course, drink a lot of water (sometimes our body confuses the feeling of hunger and thirst).
      Just don’t give and find your balanced life without others expectations.

      Much love,
      Tired and exhausted

  6. Wrist Pains says:

    Dear Cassey,

    I’m doing the Hot Girl Summer Sculpt right now, and I’m on the 4th day! I really enjoy the workouts, but I do have a wrist problem so any of the exercises that involve pressing my palm on the floor (like oil riggers, push-ups, etc.) is really painful! What sort of modifications can I make with these types of workouts?

    Wrist Pains

    1. Ali says:

      I also have the exact same wrist pains! Any tips would be appreciated!

      1. here to help says:

        try going on your forearms instead !

  7. Siobhan says:

    Dear Cassey,
    I’d love it if you could give us some podcast recommendations! I remember you talking about podcasts you love in videos, but I would love a list 📝

  8. Alice says:

    Dear Casey,
    I have only came across you few weeks ago but absolutely love your workouts and posts!
    I’d like to know your take on finding balance with different workouts.
    For example I love your workouts, kickboxing, relaxing yoga and weight training but of course I do not have enough time in a day to do them all and I prefer to do programmes that range from 2-8 weeks but I’m worried I should pick just one I enjoy?
    My reason for this is I’m worried if I for example do I finish your newest hotgirlsummersculpt and then go back to weight training and maybe some kickboxing following it, by the time I come back to you my body won’t be used to the range of moves anymore so it will be like going backwards or with weight training having to go back to lower weights and never quite getting further because I’m never sticking to just one form of exercise and so constantly losing progress I worked hard on.
    Is there any balance that can be found?
    Thank you!

  9. Goals says:

    Dear Casey,
    I plan my meals in advance and they are healthy. After I finish a meal I have a craving for something sweet which tends to lead me to go over my calorie goal. I have not been losing weight and staying around the same weight this entire time. How can I better stick to my calorie goals.

  10. Heidi Mcmahon says:

    Dear Cassey,

    Any tips for someone who has feet that go out like a duck. It is difficult to do lunges and curtsy lunges. Thanks!

    1. Blair says:

      I have rarely found someone else who’s feet go out like a duck! I don’t have answers for you but I am so happy I’m not alone! I know exactly how you feel, and some workout are just SO difficult!

  11. Directionally Confused says:

    Dear Cassey,
    I’ve been struggling recently with feeling like my workouts aren’t getting me anywhere. I know fitness and exercise are SUPER important to stay healthy, but I don’t have any set goals I’m trying to achieve and I don’t know how to go about setting goals for myself that will keep me motivated! I feel like I’m exercising just so that I have a “better” body, which doesn’t motivate me other than the need to look/be healthy. How do I set goals for myself to stay motivated, but not get frustrated when I fall short of the goal?

    Thank you!
    Sincerely, Directionally Confused

  12. Eleen says:

    Dear Cassey, I can ‘t do squats or lunges due to my knee issue. What alternative yet effective exercise I should focus?

  13. Magdalyn says:

    Dear Cassey, I’m 14 going in 15 in a few months and I was thinking about doing the 90 day journey. I would like to do it because I want to eat healthy and just feel better for myself. However, I’m having thoughts like “is it okay for me to do?” and “should I be doing this at a young age?”. Should I do this journey? From, Confused Teen

    1. Holly says:

      My opinion (take Cassey’s over mine), is that you are never too young to care about your overall bodily heath. BUT I would just advise to make sure you are doing it for that reason- not because you feel like you need to lose weight. Because you are so young, remember that you are still growing and WILL naturally and HEALTHFULLY be gaining weight. my advise? Don’t weigh yourself or exercise and eat nutritious meals just to look a certain way, but do what makes you feel best inside for you!! If that means exercising to Cassey’s videos then that’s great! Love your body <33

  14. Anon says:

    Dear Cassey,

    Whenever I try leg raises or ab moves that involve moving my legs, my hip POPS. It’s doesn’t hurt, but I’m not sure it’s healthy. How can I go about changing this?


    1. Kiandra says:

      I know about this one. So basically its called crepitus and it happens when you don’t move your joints enough so they start making that popping sound when you work then out suddenly. With consistent exercise it will probably go away. Its common with aging and it also might be due to a sedentary life style.

    2. Mel says:

      Mine does the same! It’s embarassing in yoga class. I’m going to get an adjustment from a chiropractor

  15. Healthy Doesn't Feel Healthy says:

    Dear Cassey,

    I feel like I’ve been so focused on trying to be healthy and taking care of myself that it’s actually starting to feel like a burden. I’m currently in my first year of working in a school, and this year has been extremely difficult with COVID. I’m also planning my wedding that’s about a month away that was supposed to be last summer but was rescheduled due to COVID. Between these two things, I feel like I’m beyond exhausted and stressed.

    I work out every morning, drink plenty of water, try to get decent sleep, and try to eat healthy because I will feel gross if I don’t. I’ve been keeping track of my healthy habits using the fitness planner. All of these healthy habits are starting to feel like more work mixed in with the stress of my job and wedding planner.

    I’m hitting the point that I just feel exhausted and lost on what to do. Usually, these healthy habits make me feel really good, but the stress is affecting every aspect of my life and making it difficult to take care of myself.

    Do you have any advice on how I can maintain the healthy habits that I know are good for me without feeling overwhelmed by it?

  16. anonymous says:

    I have heard of a different 80/20 rule when it comes to diet and your body. I was told 80 percent was your actions (nutrition, exercise, sleep) and 20 percent was your genetic makeup. I dont know if there is any scientific proof
    for that theory. I think its just an easy way to show that people could follow the exact program and processes and have different results. All bodies are different so doing a direct comparison isn’t worth the heartache.

  17. Rupsa says:

    Dear Cassey
    First of all you are one of the beautiful souls I have ever met! Your workouts are soo incredible and it’s helping me a lot…I have signed up for the HOT GIRL SUMMER SCULT and it’s gonna be amazing I know!
    You always say that a workout buddy always gives you more motivation and energy to workout!
    But I don’t have any… none of my friends are interested in fitness ! I hope you can help me with this….or what to do in this case…! Though you are there and I love to workout with you ! Another thing is that I am just 13 and fitness means everything to me !
    Thank you…!

  18. Behnaz says:

    Love this post!