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When it comes to GLP-1 medications, your age and stage of life matter more than a lot of people realize. What works for your body at 25 won't work the same way at 45... and definitely not at 65.

Yet somehow, most people are still being treated with a one-size-fits-all approach. Same advice, same dosing strategy, same conversation — regardless of whether you're navigating PCOS in your twenties, perimenopause in your forties, or trying to protect your muscle mass in your sixties. And that disconnect might be exactly why things feel harder than they should.

Here's what I watch for at every stage of life, so you can make sure what you're doing is helping, not holding you back.

Ages 18–34: Fertility, PCOS, and Building Your Metabolic Foundation

This stage is less about quick results and more about setting up your long-term health. There are three big areas I’m always thinking about:

• Fertility (for everyone): As weight and metabolic health improve, hormone balance shifts. That can mean more regular cycles, improved testosterone levels, and a real increase in the chance of pregnancy (even for people who’ve struggled before). This often catches people off guard, so it’s something we need to plan for, not react to.
• Metabolic foundation: Insulin resistance and early cardiovascular changes can start much earlier than people think. Even if you don’t see the impact yet, this is where we can start to reverse that trajectory and set you up for better long-term health.
• Your relationship with food: This is your opportunity to move away from restriction, all-or-nothing thinking, and diet culture patterns and build something sustainable that lasts into the next phase of life. 

Late 30s–50s: Hormones Change Everything

This is the stage where many people start to feel like their body has suddenly stopped responding.

Perimenopause and menopause bring real physiological changes. You start to see shifts in hormones that affect appetite, fat distribution, sleep, and stress levels. What worked in your twenties often stops working here, and it’s not a lack of effort. It’s biology.

The challenge is that these symptoms are often overlooked or misattributed. Instead of addressing hormonal changes, many people are told it’s just stress or anxiety, or everything is blamed on weight. That delay in proper support can make progress feel nearly impossible.

Sleep and stress also become much more impactful. Poor sleep alone can drive hunger, increase cravings, and create resistance to weight loss. Add in higher cortisol levels, and it becomes even harder to see progress using the same strategies as before.

If there’s one shift here, it’s this: your body isn’t broken—it just needs a different approach.

60+: Focus on Preservation, Not Just Loss

In this stage, the goal can’t just be weight loss.

One of the biggest risks with GLP-1 medications later in life is losing muscle along with weight. And that’s not a small issue. <uscle is directly tied to strength, stability, and independence. Losing too much, too quickly, can actually make someone more vulnerable, even if the number on the scale is going down.

This is why the focus shifts toward preservation. Protecting muscle becomes just as important (if not more important) than losing weight.

A few things really matter here:

• Prioritizing protein intake
• Including some form of resistance training
• Avoiding overly aggressive dosing or rapid weight loss

It doesn’t need to be complicated or intense, but it does need to be consistent. Because at this stage, we’re not just thinking about weight, we’re thinking about long-term function and quality of life.

What Matters at Every Stage

While the focus changes over time, there are a few things that matter no matter your age.

• Muscle matters at every age. In your 20s you're building it. In your 40s you're protecting it. In your 70s you're fighting to preserve it. But you can gain muscle at any age — the rate just looks different.
• Bone health, especially for women over 40. Declining estrogen and rapid weight loss can both accelerate bone density loss. This needs to be monitored, not ignored.
• The goal is metabolic health, not just weight loss. The number on the scale is one data point. Body composition, strength, energy, and hormonal health tell a much fuller story.
• Match the strategy to the stage. That's when things finally start to feel easier.

Want to Hear the Full Conversation?

This episode of The Obesity Guide goes deeper into each phase, including the specific questions to ask your doctor, real patient stories, and practical steps you can take right now. Use the timestamps in the show notes to skip straight to your age group, or listen all the way through.

And if you want more real answers to real questions, including longer deep dives on side effects, GLP-1 management, and metabolic health, come find me on YouTube at @MattheaRenteaMD. 

TRANSCRIPT:

Disclaimer: The transcript below is provided for your convenience and may contain typos, errors, or grammatical inconsistencies, as it has not been professionally edited or proofread. Please enjoy it as-is and read at your own discretion.

Please note: The content shared in this podcast and blog post is for informational and educational purposes only and is not intended as medical advice. Always consult your healthcare provider for personalized medical guidance.    

 Welcome back to another episode of the podcast. How are you all doing? I have been loving this time of year. I know I talk a lot about this when spring comes, when I can hear the birds, when I see the trees start to bloom, I feel like there's hope again, I'm slightly going through mourning in the sense that the high school.

Gym and walking track that I go to. So it's a public high school by me. You pay this next to nothing amount per year. The gym itself, that's multiple basketball courts on the outside perimeter of it, there's a walking track. I've been doing this a really long time. And then they have a weight room that is free weights and machines.

Well that's closing down here at the. End of March I'm happy for the school. It'll be this multimillion dollar renovation. Amazing for them. That building has not been touched since the 1980s, and you can tell however that means that's closing now. I thought that that meant I was gonna have to join somewhere else.

I love this place because it's literally like four minutes from me. It's not quite walkable based on the roads, but again, in the car it's super quick and so it's so easy to get there and to come back in the mornings. But what's really nice is they're now opening a different gym at that school. For us to come and walk in the morning, the hours won't be as long, but you know, me, I'm up early, so that won't, that will not be affecting me.

I'm really grateful that they're doing that. 'cause I really didn't wanna have to join somewhere that would be. 20, 30 minutes away because at that point, by the time you get there and you come back, that is the hour walk. I'm really about efficiency, especially if you have a busy family. You know what I'm talking about.

So anyway, so that's the silver lining of what's happening. And then the other thing that I've been working on, I. I don't know if I've talked about it on the podcast, but I've decided to do a little bit more on YouTube. What I realize is, I've always made these short form videos, 1, 2, 3 minutes on TikTok, and they go over to Instagram and they, they post on YouTube as well, but I wasn't doing a.

Longer form answers where it's maybe 10 minutes, 20 minutes, 30 minutes, things like that. And it's not the podcast. These are separate topics where I'm answering questions, if you don't follow me over on YouTube, if you're someone that spends time there, make sure that you find me there.

So I'm Mattia MD the same username that's on. Every other, platform. And I'll make sure, that we put underneath this video a link to that and the, the few things that I'm doing over there right now, I'm doing a series Real Questions, real Answers. These are questions that I did a Reddit ask me anything recently and there were really good questions.

I. Read those questions and then did answers to them. So in the Reddit thread, I'll make sure to link that as well. You can go check that group out. There's written answers that I have, but this is me talking in more depth about the different things that I get asked. And I think I'm gonna continue this series.

Also, maybe questions that I get under videos and TikTok, things like that. A fan mail, right? I'm gonna bring a lot more of that over there. So that's one series. And then the other. Thing that I do a lot is I talk about side effects and how to manage different things, and I have playlists that are created for this.

If you wanna go in and you wanna just, hear about constipation or fatigue, things like that, you can just click on the GLP one side effect playlist. Or if you wanna hear questions and answers, things like that, you could click on that one. Hopefully it's really easy to navigate.

Alright, today I'm gonna talk about what I think about. In all the different decades of life when I'm seeing my patients. I got some really good fan mail here recently, and people were asking me, they were saying, one person said, Hey, well I'm in my thirties and you've never talked about specifically in your thirties, what do you watch out for?

And I had a lot of people write to me, well, I'm in my seventies, and what about bone health? What about this? What about that? People want to know specifically for their age. What are things that are looked for, and hopefully your physician can help you specifically with that. But I am gonna talk in broad strokes today.

I sort of see a few different areas. I see this sort of, fertility and prevention area when we're in the twenties, thirties. When I think about later thirties into the fifties, I think about hormonal transition phase, and then I think about 60 or 65 plus as really a prevention phase. And then there's gonna be some things that span across.

All decades. It's called like the middle layer. So it's going across everything and that's gonna be like muscle matters at every age. I'll get into tho some of those. The either applies to everybody, categories or special consideration, like bone health and women over 40. I'll get to some of those at the end of the episode, but I'm gonna just go through here, each different area.

I know a lot of you might think, oh, well, I don't care about this age or that age. I only care about mine if that's the way you're thinking. There are timestamps underneath this podcast. In the show notes, there's timestamps that says, Hey, at this minute, she starts to talk about.

Or that phase or that age. So you could do that. Okay, so let's start with number one here. I wanna talk about really 18 and over, but really think 20 to 30 years old. This is what I am grossly terming the fertility and prevention phase.

The, and this is not just fertility for women. It's an increased chance of pregnancy for, I think, obviously women getting pregnant, but also the male. His sperm being more potent fertility wise when he's lost weight because of how the testosterone changes. There's something called sex hormone binding globulin. When you are overweight, you are masking the testosterone that's there. It looks like your testosterone's low, but it's because the weight is changing what is available to be used. When you lose weight, oftentimes men. Their libido goes up, they're feeling better, the chance of pregnancy goes up.

I bring this up because this isn't just a woman problem. This is also, everyone needs to care about this. Right? And oftentimes if you have a couple, and, let's say they go from, obesity or overweight, and they both really work on it and suddenly there was a pregnancy, it's often because both partners got more healthy.

It's not always just the woman. And in fact, I hate that we do that in the fertility world where we only. Point to the woman. That's a, that's a side conversation. But so when I am having, anyone who has a uterus and has not gone through menopause, I am thinking about them not getting pregnant if they're on a GLP one medication.

And again, also the fertility rate's going up because people will tell me, well, I haven't been able to get pregnant for 10 years. This doesn't matter. I've got news for you. There's a chance that you get pregnant because before it might've been PCOS that was not treated properly. Finally, we're starting to restore cycles, right?

That cycle regularity is huge with my PCOS patients and suddenly surprise, you're having a pregnancy. If that's actually wanted, okay, fine. But if that's not the intended consequence, we really wanna make sure that, do you have an IUD in place? Are you using oral birth control? Is a significant other, getting a vasectomy.

What's the setup and how can we make sure that you are not getting an unwanted pregnancy? And then I'm also really thinking about in this 20, 30-year-old category, I'm thinking about metabolic foundation building. Can we start to get this insulin resistance under control? What really matters here is that you do start to get metabolic damage at an early age, and this is when you start to get, if you have.

Insulin resistance, you start to get that, that soft plaque buildup. It might only show up when you're 50. You get a heart scan, a heart screening, a calcium score, and you see that there's plaque there. Okay? It maybe took 10 years for that to show up on there. This is the time for us to start to work on that.

And then the third really big thing that I think about in this category, it's the relationship with food. Can we start to undo some of that diet culture and for the rest of your life, put you on a different trajectory. Some of the favorite patients that I work with, they are 18 years old, 20,21. They are very young and they can learn something different from me.

I'm not gonna screw them up with telling them calorie counting. I'm really thinking, okay, what do the next few years look like for you? If they're headed to college that next year, we're not doing things that aren't sustainable. I think to myself, oh my gosh, their whole life potentially can be different because of this.

These are things that we care about that hormonally things start to be. Regulated again in a way that makes sense for you, that the foundation of what you're doing really changes the long-term trajectory of your health and that your relationship with food your body movement, that we start to rewrite some of that and it doesn't matter if it takes us 10, 15 years to quote unquote change it and get it right.

You're starting to work on this at an age when you're really. Incredibly responsive and that's gonna be what you carry forward. That's really what I think about in the 20 to 30-year-old range. And then the second category, I start to think about really 35 and over, but later thirties. Most women, forties, definitely by fifties.

I think about a hormonal transition period. Going from perimenopause into menopause. When I think about the hormones shifting, I think about it impacting fat distribution, appetite, sleep, cortisol levels, this is really a period where, number one, I wanna make sure that this is being addressed, if not by me in some capacity, if I can.

Otherwise, are they seeing gyn, are they seeing a women's health, specialist an endocrinologist? Different physicians have different amounts of training in this, and I wanna say something that's really disheartening If you suffer with. Obesity or overweight, chances are really good that you are not gonna be taken seriously because everything is blamed on your weight the bias is so high that you're not given HRT hormone replacement therapy.

When someone else, if they came in a smaller body, there'd be no question to just give them, and they would know that. I had a patient, she gave me permission to talk about this. She went in classic menopause symptoms. I'm talking sleep disturbance, hot flashes, just you name it, she had it. She goes in and the physician said, oh, I think you're anxious.

Here's an SSRI. If anyone in a different body came into that office, they would be given HRT immediately. And apparently this physician was trained in menopause. There are certain certifications that physicians can go through to learn more in this area. It's something where eventually I just have to do it because I'm so sick of hearing a lot of this.

Super crappy care that I hear my patients get. And so we end up advocating for a different physician or I end up recommending someone to them. So it all ends up being okay in the end, but it's annoying the fact that they have to go through all those visits where they're not being heard. I remember hearing this in the past that, what was it like nine or 10 visits that a woman had to go through before she got appropriate care for the menopausal symptoms?

And it's as simple as. You come in with palpitations and they're not realizing this is part of you going through perimenopause into menopause, they don't know okay that the frozen shoulder, right? All these things aren't being put together. So your physician is frankensteining things together, but not realizing, oh, but this is what's, this is what's at the heart of it.

This is what we actually need to look at, right? This becomes very important because. You have a harder time making progress if you actually need HRT and we're not doing it. We know nowadays there's a study evidence behind this that women that are on both HRT and GLP ones, that they have a slightly greater edge as far as being able to get better results.

Again, there's a lot of people that maybe don't qualify for this or that don't need this, but it's something to consider if someone's struggling both. Symptom-wise, how they're feeling, the ability to achieve results. There's a lot that goes into this, and it's not in someone's mind when they're working really hard and can't achieve it,

i'm really focused on hormones during this period. I really think about sleep disruption. It causes weight resistance. It's impossible to make weight progress when you are constantly not able to sleep. These are things that we have to manage. We have to manage stress and cortisol a lot more.

As we enter 40, 50, 60, and beyond, you don't have that reserve anymore. Hormonally things really change with that. So what worked at 25? It's not working at 45 anymore. There's nothing wrong with you, and this is where many women, they feel like their body, quote unquote, stops working.

And they'll say, I'm eating the same, but my body shape is changing. It's just changing signaling and we need to work with that. So nothing wrong, but the hormonal aspect needs to be addressed. Otherwise, I see people really struggle. Okay. The third category that I see is really my 60 plus, or technically, if you say 65 and over, that is.

An older category where we start to classify things differently. I wanna call this the preservation phase. The key here being your sarcopenia risk, meaning you lose weight, but really it's all muscle and you actually got sicker. That rapid weight loss, the chance of that, the body composition becoming worse, even though the scale you think is improving, but body composition becomes worse, the chance of that is just through the roof.

What I really think about in this age group is always, but especially in this age group, protein really becomes non-negotiable with this group resistance training. It's medicine. This is not optional. This is not If I want to do it, you've got to do it.

Does it need to be hard and complicated and 70% of your one rep max and all this craziness? No, 10 minutes, three times a week, but can you do it consistently? I don't care if it's YouTube, I don't care if it's Peloton. I don't care if it's Dr. Ali Naski. I love her stuff. If you like her, the 10 minutes, three times a week, that beginner strength course, the level 1, 2, 3, where one is you could literally be holding onto a chair.

Level three is more advanced. I love that. In the clinic you can always email us 'cause we're able to, get you that program through the clinic. She's made it now where it has to come through a clinic. I love all these things, but you've gotta do them consistently. Because I'm actually not even caring anymore about just what your weight is.

At this stage, I care just as much, if not more, about what you're keeping than what you're losing. And every stage I cared about it, but at this point it just sometimes becomes harder to recover it.

Things that I care about for everyone. Muscle matters at every age, you could think about twenties, maybe you're building it, maybe forties. You're protecting it in seventies. You're fighting to preserve it. But the reality is you can really gain muscle at any age. It's just the speed of it I see.

Be different. And the rate of the muscle loss I see be different. So I'm gonna give that one classic example. I said this story endlessly on the podcast. I one time had someone join my clinic that. Did not want to do what I was recommending. And within two, three months what I was seeing with body composition, the rate of muscle loss was horrifying.

And I had told this person, we're gonna have to do things really differently. The dose of the medication's too high for you if this is happening. 'cause I'm not just about weight going down. If all of its muscle, you literally have got sicker. I helped you in no way that's harming you.

So I wanted to do that. I wanted. Changes in what they're eating and how they were moving, all these kind of things. This person didn't wanna do it and they left my clinic. But you know what? I thought to myself, at least they're not under the delusion that they're getting healthier just because, quote unquote, the number on the scales going down.

They knew that was bad news. I know how detrimental it is to their future if we're in their sixties doing that kind of damage to them.

I don't want them to have a fall in their eighties and. Bad things happen because we were just chasing weight loss when they were 60. I'm not gonna be part of that. That's, I'm not excited about that. So those are the different phases I think about. The other thing that I really care about is bone health, especially women 40 and over.

When estrogen's declining in your bone, health can get worse, and especially rapid weight loss as well. You can have that worsening with the bone i'm thinking about bone density, not just weight. And so this is where all roads lead to Rome. You have to care about all of it the other consideration that I have is typically as we get older, it's go low, go slow. You're more side effect sensitive as you get older this is not a bad thing, frankly, I care about this even in my 18-year-old patients, but it's just that you really don't want someone who's a cowboy about it.

That's why all these online clinics that are not ever meeting with you, they're just every single month increasing the dose. They're never talking to you. They have no idea what's happening. That is so scary to me because it really is dangerous depending on who you're dealing with, doing it in that way.

Okay. Everything, though, the way I do it, we're shifting from this being weight loss to being about metabolic health. Can we preserve the muscle? Can we make you stronger? Can we actually get you healthier? So your body, it's not working against you. It's working different at every age. And we need to match the strategy to the stage, that's when things finally start to feel easier, which is what I want for you. All right, that's what I've got for today. I hope that you have an awesome rest of the week and I'll see you next week.