Is Dieting Dangerous For Your Metabolism?

Hey guys!

I’ve told you all about my history with extreme dieting, an unhealthy relationship with food and obsession with the scale. It affected my entire body in a way that took me years to heal.

One of the hardest things to heal was my metabolism. I was tired, I was cranky (ask Sam), and once I let go of the strict cycle of dieting I had been on, there was no rhyme or reason to my weight. Sometimes, I would eat a salad and gain weight, but then eat pizza and lose weight? It was crazy!

But then I looked back and realized the damage I had been doing to my body. I’d cut calories and exercise more, lose a little weight, and then hit a plateau. So then I’d repeat the cycle. Cut MORE calories, exercise more, etc.

I was malnourished and my body was tired.

It took me YEARS to fix the damage I had done. After it had already taken me years to see what dieting was doing to me. So it got me wondering, how exactly does dieting affect your metabolism? Does it actually cause damage? What’s going on in our bodies when we repeat the diet, lose weight, plateau cycle?

A little metabolism 101

Okay, so your metabolism is basically the system that produces and uses energy to keep your body alive. Things like:

  • Breathing
  • Blood circulation
  • Temperature regulation
  • Digestion
  • Brain function

Your body burns calories even while you’re resting to keep these processes going. Those calories are pretty important, and they come from what you eat and drink.

So how many calories do you need to make sure your body has the energy it needs to function? This is referred to as your basal metabolic rate (BMR), and it depends on factors like your age, height, weight, and how much lean body mass you have. You can get an estimate with a calculator like this one.

As you know, calorie imbalance (burning more than you eat, or eating more than you burn) is what causes weight loss or weight gain. You eat calories, your body burns some to function, and burns more depending on your activity level. If you’re left with excess calories, you may gain weight. If you’re in a calorie deficit, you may lose weight.

This is where I took it too far. I was cutting too much too fast. Every time I’d hit a plateau, I’d cut more. I was definitely eating less than what my body needed at minimum, let alone enough to sustain with HOURS of exercise every day.

Does dieting damage your metabolism?

More like dieting DISRUPTS the metabolism.

But that doesn’t mean it’s an easy fix.

Basically, dieting throws a wrench in the hormones that regulate your metabolism: leptin and ghrelin are the big ones, but cortisol can come into play too. These hormones affect your hunger, fullness, and energy levels. Let’s break it down a little more (don’t worry, we’ll keep it simple!)

Leptin: Normally, your fat cells release leptin when they’re stored. This signals to your body that you have some extra energy to use, which makes you feel less hungry. When you lose weight (especially too quickly), your body doesn’t release as much leptin. Less leptin = higher appetite.

Ghrelin: This hormone does the opposite of leptin. It makes you feel hungry.

Cortisol: This is a stress hormone! But dieting can raise cortisol too. This is important because cortisol actually causes weight gain.

There are more players to this game, but we’re keeping it simple okay?! What’s important here is that these hormones work to keep you alive. Your body doesn’t know that you want to lose weight just to feel more confident in a bikini. If you suddenly make extreme changes to the energy you’re taking in by cutting calories and/or exercising a lot, your body is going to shift gears to survive. Maybe you’ll feel less satisfied or more hungry. Maybe your body will hold onto fat or use muscle for energy.

Our bodies are so amazing to adapt like that. But think about what happens if we keep going deeper into dieting. Every time your body adapts, we push it harder. So it pushes back. After cycling through that for so long, you can’t really just go back to eating “normal.” Which is exactly what I tried to do once I realized how unhealthy my lifestyle had become.

I added carbs back into my diet and even though I was still eating healthy foods and exercising, I kept gradually gaining weight. For like 3 years. On top of that I was:

  • Tired
  • Foggy
  • Having trouble sleeping
  • Cold
  • Hungry ALL THE TIME
  • Grumpy
  • Experiencing digestive issues

I knew I needed to stop focusing on how I looked, no matter how frustrated I was. I needed to focus on my health.

Healing your metabolism

The most important thing is to give your body time and plenty of rest. The stress that dieting puts on your body is A LOT.

Next, give up the “dieting” mentality, and feed your body balanced, nutritious meals. Eat when you’re hungry and don’t stress about it. Getting enough carbs, protein, and fat will help your hormones reset and start working as they should again.

Finally, keep exercising, but stop doing hours of cardio. Find something you love to do and add in some light weight training to build lean muscle.

Most importantly, make changes that will help you avoid falling into the cycle of dieting again. 

You can lose weight and change your body without your body fighting back. You can do it in a healthy, sustainable way. Diets don’t work because they put too much on your body too quickly. If your body thinks it might be starving, you’ll end up doing more harm than good and any weight you lose will probably come right back.

If you want to lose weight, do it slowly. Make small changes to your diet and pay attention to how you feel. Don’t feel pressured to overdo it on exercise, and give your body plenty of rest.

18 thoughts on “Is Dieting Dangerous For Your Metabolism?”

There are 18 comments posted by our users.

Leave a Reply

Your email address will not be published. Required fields are marked *

  1. Prachi Shah says:

    Thank you for sharing a useful and interesting article! I am also trying to lose weight but I can not get success. Thank you for giving wonderful advice. I should follow all your tips and reduce the weight.

  2. Joyce says:

    Thanks Cassey, wish I had read this earlier so I wouldn’t suffer the pain I am going through now. I KNEW I am definitely not fat since I can easily fit in an 11-year-old girl’s t-shirt as a woman in her 30s. I was eating healthy before and doing weight lifting exercise twice or 3 times a week and have been following your pilates exercises too. It all started with me moving house last year. Because of the lockdown rules here, I was able to get help from friends and because I’m an immigrant I don’t have any family in the country, so I did EVERYTHING on my own. I did a lot of labour work, moving stuff, packing and tidying, but no time to cook, and too tired to eat. For almost a whole month I was on diet and over-exercising “passively” without knowing it. I lost 3kg in that month, but my body revenged. After settled down, I started feeling hungry constantly, craving sugar and sweets, and I couldn’t control myself. I quickly put back even more weight in weeks, had lots of troubles like bloating stomach and constipation. Then just after the New Year, I decided to go on diet and that opened Pandora’s box. I was eager to get back to the weight I was, ate too little but exercised too much, my weight dropped dramatically and I started losing sleep, hair and my period. Now I am so worried, I know there is something wrong with me, with my body and with my mind, but I can’t help to think about calories when eating, and can’t stop exercising, I feel guilty if I don’t. After a long night without sleep, I cried today, loud, to let out all the stress. After reading your article Cassey, I put my scales away, deleted the calories counting apps. I have decided, from now on, to eat the same healthy food I have been practising in the last two months but eat the correct quantity. Hopefully, in this way, I am able to slowly recover and I do wish it doesn’t take as long as 3 years. Thank you for making me made this decision, and made me feels much better. I look forward to seeing you sharing what you did to recover.

  3. AdrianaV says:

    Thanks for this balanced post. I feel the same way, I’ve done every diet out there and now years later I’m paying the consequences, it would be so nice to go back in time and tell my younger self to stop fad dieting! But thankfully I’m getting on track now thanks to people like you who promote a healthy balanced view of nutrition and exercise.

  4. I recommend yoga exercise. It works for me.

  5. Faith says:

    I feel very identified with what you describe and I am just like you were before. I try being super strict and feel heavier and eat pizza and look thinner the next day (sometimes). You explain this but gloss over the solution. Can you lead me to a more detailed explanation on what you did those years afterwards where you recovered?

  6. Elona says:

    ……..but what happens when what you love is hours of cardio……….
    Great post, it was super informative 😊

  7. Jennifer says:

    Hi Cassey! This makes so much sense. I have probably tried every diet in the book and I’m still miserable and not where I want to be health-wise/body-wise. My mother was a chronic yo-yo dieter and that’s how I grew up. I would say that I’ve been on some sort of restrictive diet for the majority of my life (I’m 36) and I’ve never been happy with my body, how I feel or how I look. I was bullied when I was younger for how I looked and I was called “bubble butt” and “thunder thighs” and it has stuck with me. I am afraid of food, I am afraid of getting fat. I feel guilty every time I eat and I feel out of control if I don’t have each meal planned down to each macro/calorie that I think fits me but obviously doesn’t because nothing has changed. I feel stuck and depressed. I don’t know how to let go or where to start. Of all the research I’ve done on everything, I find something that contradicts that information and then I’m back to square 1. I burn (according to my Fitbit) around 2,000 calories a day but I’m only eating under 1,000. I follow a (mainly) whole food plant based vegan diet, I workout (blogilates of course, yoga, cardio and a lot of walking) and I’m probably average weight for my age and height but I don’t feel good in my body. I feel like everything I eat I have to burn off or I feel bloated or think that I’m eating too much healthy fat or too many carbs. I need help letting it all go.

  8. I was diagnosed with polycystic ovary syndrome at a very young age and as a teenager I am having a hard time to cope up with what is going on with my metabolism. In our country, access to nutritious food is difficult and after reading this blog, I realized that I might have done some damage with my body and health. I worked out with you for almost 5 years now and I hope that in the succeeding years I find myself achieving sustainability.

  9. Jackie Nefdt says:

    Thanks, Cassey. This is such a gentle and humanizing approach to getting healthier after disrupting (damaging your metabolism). I’ve put my health on the back burner for year and really struggled to make time and space for health eating, but its not an all or nothing situation. I’ve made some small changes for the last four months, and they’ve paid off slowly, but more importantly, sustainably. I used to only let myself eat salads when I ate out for years, and that amongst other behaviors made me feel really deprived and sad. Now I take joy in eating a salad because its not a rule that I have to follow, just an option that helps me work on my triglycerides and other health goals. Its a much healthier mentality, and this post really makes me feel supported and seen.

  10. Audrey says:

    Hi Cassey!
    I was wondering if it would be possible for you to do a post on eating and exercising while pregnant and/or breastfeeding! I’ve been breastfeeding for almost 9 months and it’s been hard for me to balance taking care of myself and my baby. I know it’s a small audience in your following but I’m feeling lost. Love your posts!

    1. Lisa says:

      I breastfed for over 2 years. All that time, all I did for myself (bodywise) was walking as it was the only activity that did not make my milk supply change in volume and possibly taste. After I finished, I was able to start full exercising without any concerns about my baby girl. I feel now that it was worth the wait. You are not alone in this, but our babies is little for such a short time, and breastfeeding is even shorter, that I personally decided that weight loss can wait, and my body actually agreed and shed 10 kgs in 10 months once it was not required to store fat for milk production. Take care, maybe try something else that makes you happy (for me it was drawing, reading, cooking) and enjoy your little baby.

    2. Anna Belle says:

      I breastfed until my baby was 3. (The last year was really once a day before bed.) I lost almost all of my baby weight within about 4-5 months, and I really think it was due to breastfeeding and a healthy lifestyle. Fast forward 10 years later, I’m older and not sure if I’ll be as lucky with bouncing back to my pre baby body so quickly! I agree with the previous post and would love a pregnancy and post baby exercise fitness routine!! Or if Cassey gets pregnant, maybe she can blog and post about her journey and we can follow along… 🙂

  11. Chloee Jean says:

    Hi Cassey!

    I really want to get myself on a healthier lifestyle, but I’m not able to afford your 90 Day Journey program due to me being out of work because of COVID. Would you, by any chance, be willing to share tips on how to create a healthier life style with lasting results?!

    Thanks 💛

    1. kokomo says:

      Im not a pro, so take this with a grain of salt, but id recommend her monthly calendars, since they work through YT videos, so you can work out from home.

  12. Mathilde says:

    So nice to read all this! I’m about to start the omnivore 90 day journey meal plan on first march. I’m lucky i’ve read this article before! Thank you so much Cassie to enlighten us with all your experiences!

    1. Mathilde says:

      Cassey** So sorryyy

  13. Larina says:

    Dear Cassey
    Thank you for this blog entry. I experienced the same thing. My tip for all people its much more longlasting if you find a balanced nutritition, allow yourself what you like in a suitable manner. Due to my experiences restirction do not help you to reach your aim. For sure you will probably use weight for a little bit of time, but then comes the plateau, which might make you feel you are not doing the right thing. Leading to you to put even more restrictions on you. You may achieve your aimed scale for instance, but your feeling tired, your grumpy. Do not let this happen. What is really the point is, that your feeling happy with your body. Remeber other people can see and feel whether your feeling good, being in peace with your body will make you much more beautiful for others than having skinny body with out the acceptance of your self.
    What helped me, was to go on hikes or helping my grandmother in her slow manner and setting the aim to add carbs to my meals at least once a day. Just start slowly, listen into yourself.
    Lots of Love

  14. What are some of your best tips for healing the metabolism? I’d love to see more insight on that! I’m currently in the process of healing my metabolism after years of trashing it and just not realizing the damage I was doing. I was cold all the time and had a really low heart rate – I thought it was admirable because that meant I was in “excellent cardio health”…wrong! I’ve been working on improving these things and slowly but surely it’s working! And I’m warm! YAY! Anyway, would love to hear your ideas in another blog post! 🙂