Ultra-processed foods harm men’s health. They increase weight, disrupt hormones, decrease testosterone, and introduce harmful substances linked to declining sperm quality. They contain industrial and synthetic ingredients. This may be why over the past 50 years, sperm quality has plummeted.

[u/mvea]

https://cbmr.ku.dk/news/2025/not-all-calories-are-equal-ultra-processed-foods-harm-mens-health/

[u/mrlazyboy]

I’m gonna be honest, this is yet another example of most likely being overweight impacting everything else.

Being overweight disrupts hormones and decreases testosterone. Doesn’t matter if you eat ultra-processed foods or fruit. If you are overweight, odds are higher that you will experience these problems.

[u/bUrdeN555 → u/mrlazyboy]

Or both? Ultra processed foods do make you fat but they also include harmful ingredients.

[u/mrlazyboy → u/bUrdeN555]

How do ultra processed foods make you fat?

I’ll be more specific - my TDEE is 2800 calories. If I eat 2800 calories of twinkies or apples, my tissue mass will remain the same.

Eating too many calories makes you fat. The fact that I use whey protein powder (one of the most processed foods you can eat) has not made me fat. In fact, I lost 50 pounds using it.

[u/chili_cold_blood → u/mrlazyboy]

my TDEE is 2800 calories. If I eat 2800 calories of twinkies or apples, my tissue mass will remain the same.

The problem with this reasoning is that what you eat affects your metabolism.

[u/mrlazyboy → u/chili_cold_blood]

The thermic effect of food is very small when you look at it in practice, and is already taken into account when you examine nutrition facts labels.

Surprisingly, the number of calories you consume has a sizeable impact on your TDEE. For example, as you diet, your body will start burning fewer calories over time due to metabolic adaptation. Conversely, if you start eating above your TDEE, your TDEE actually tends to increase slowly over time.

The biggest impact to your TDEE is genetics. Physical activity only has a minor impact.

[u/chili_cold_blood → u/mrlazyboy]

It's not just the thermic effect of food. There is also the effect of macronutrient balance on metabolism. A diet with higher fat and lower carbs can help train the body to burn fat as fuel, which is good for fat loss. A diet with higher carbs and lower fat can train the body to burn carbs as fuel, which is bad for fat loss because you won't burn much fat when your body is burning glucose, and because carbs tend to burn quick, so the body will need a constant supply to keep energy levels from crashing. Carbs can also spike blood sugar, which promotes fat storage. Also, a diet with insufficient protein can lead to muscle loss, which in turn decreases metabolism.

The biggest impact to your TDEE is genetics. Physical activity only has a minor impact.

I can burn over 4000 calories above my typical TDEE in a day of cycling. That's not a minor impact.

[u/MeateatersRLosers → u/chili_cold_blood]

I'm sorry, but I think you're reading from an tired, old playbook of keto propaganda.

The body doesn't need to be "trained" to burn anything, it burns both fat and carbs naturally throughout the day.

[u/chili_cold_blood → u/MeateatersRLosers]

The body doesn't need to be "trained" to burn anything, it burns both fat and carbs naturally throughout the day.

Metabolic flexibility can be lost and re-trained through diet. Here's a recent study demonstrating that: https://pmc.ncbi.nlm.nih.gov/articles/PMC10108759/

[u/MeateatersRLosers → u/chili_cold_blood]

I’m not really sure what’s supposed to be interesting there? Deplete your glycogen stores in your muscles and liver, your body can keep going on with fat and over time to be nudged to be a bit better at it than first starting out. Okay? That’s the cycle humans been on for a long time, no steady food, live off bodyfat a few weeks here and there. That’s how we lived for eons and the purpose of bodyfat = energy reservoir.

It also shows that people can steady state exercise but that’s long known.

I mean look at figure 3 in the study you linked. Even for the low carb high fat group, once VO2 max exertion surpasses 50% in all those graphs, fat starts shrinking in percentage of energy derived and carbohydrate rises.

Which for the low carb group means stripping either dietary protein of it nitrogen to turn into a carb, or doing so to muscle.

I think the graphs show quite the opposite of what Tim Noakes intended.

[u/chili_cold_blood → u/MeateatersRLosers]

once VO2 max exertion surpasses 50% in all those graphs, fat starts shrinking in percentage of energy derived and carbohydrate rises.

It's not possible for the system to burn a lot of fat at extremely high levels of intensity. This has been known for decades. Fat just can't be converted to energy fast enough. However, a critical result here is that, as shown in Figure 3C and 3D, the crossover from fat to carbs happens at a high level of intensity (>80% of VO2max) in the context of a low carb high fat (LCHF) diet, which counters the typical narrative that all high intensity exercise has to be fueled mainly by carbs. Also, as shown in Figure 3D, after a high carb low fat (HCLF) diet, there isn't even a crossover from carbs to fat, so the system keeps burning mainly carbs even at very low intensities, which is very ineffecient because it requires you to keep shoveling in carbs to keep energy up, and it is also bad for fat loss because the system tends to keep burning carbs when there is body fat available for fuel.

Deplete your glycogen stores in your muscles and liver, your body can keep going on with fat and over time to be nudged to be a bit better at it than first starting out.

We're not talking about a tiny nudge here. These are huge effects. As shown in Figure 4, in the LCHF diet condition, energy came from about 40-60% fat or 40-60% carbs, depending on distance. This demonstrates metabolic flexibility, because the system able to generate energy from both carbs and fat. In the HCLF condition, energy came almost entirely from carbs (90+%), which demonstrates a lack of metabolic flexibility. The VO2max test results are in the same direction.

Deplete your glycogen stores in your muscles and liver,

Nobody said anything about depleting glycogen stores. Under normal conditions, you don't need carbs to maintain glycogen or blood sugar, because you can make glucose from non-carbohydrate sources (e.g., protein) through gluconeogenesis.

[u/MeateatersRLosers → u/chili_cold_blood]

This demonstrates metabolic flexibility, because the system able to generate energy from both carbs and fat. In the HCLF condition, energy came almost entirely from carbs (90+%), which demonstrates a lack of metabolic flexibility.

I'll have to disagree. Tim Noakes treats reliance on carbohydrates as some type of disease, almost, in his language used here and elsewhere. So he puts great importance on nudging that crossover point higher, I see it as just common sense. A few days after no carbs (which the body will interpret as not getting food and local carb reserves depleted anyhow), it will switch to burning higher amounts of fat as needed.

However, the body does so by design. That's why it has glycogen stores in the muscles and livers to begin with, readily available to the muscles. If it has those, there is no reason for it to burn fat will nilly.

It might be hard for the low carb crowd to fathom, but fat is extremely rare in nature. Wild Game has 7x (1/7) LESS the fat content of domestic livestock.. Nuts and seeds were extremely seasonal and snatched up by other animals like squirrels. The avocado was ripe maybe 10 days out of a year, and 10x less flesh than what is available in supermarkets now, not to mention it being only in a region of Mexico. The olive only became edible about 7 thousand years ago or so, with the discovery of using lye to process it, otherwise it had to sit in water for months.

The only foods I can think that had a lot of fat that were more readily available was the coconut which is fairly coastal, and various sealife towards the poles -- whic is the opposite place humans evolved in, the tropics. The paleo fantasy that humans evolved eating no carbs and just sources of fat and protein is just that, fantasy. That's why the majority of modern hunter gatherer tribes have been observed eating over 70% plants.... and that crossed over to 80% often.

Humans are also not able to efficiently turn carbohydrates into bodyfat, so over 90% of someone's bodyfat is typically from dietary fat. They know this both experimentally and from biopsies of fat tissue and analyzing it.

In that sense, it would make no sense for humans to be "metabolically flexible" during normal times and burn fat in equal amounts. It's like burning your reserve tank of gas during normal operation. Most organs run fine on carbohydrates, some like the brain greatly prefer it, and some regions of the brain even require it (hence the body will strip muscle to convert to carb to provide it). However, something like the heart runs primarily on fat -- so for that and other uses it would be a really bad idea to run down fat reserves in nature when it simply wasn't required.

We've known from the Minnesota Starvation Study from WW2, as well as concentration camps, the inmates who died of starvation, often did so after the body ran under a certain threshhold of bodyfat it required, rather than lack of muscle.

Nobody said anything about depleting glycogen stores. Under normal conditions, you don't need carbs to maintain glycogen or blood sugar, because you can make glucose from non-carbohydrate sources (e.g., protein) through gluconeogenesis.

That study the low fat group was eating 6% calories from carbs. That will easily enter someone, especially an athlete, into ketosis. I've done this enough, you lose a lot of "weight" the first few days, mostly through pee, but it's the 4 parts of water that was bound with each part of glycogen in the muscle.

In this state, your body does not make enough glucose to resupply the glycogen in the muscles or the liver. It makes enough to run the brain and, as you said, maintain blood sugar (which is how it gets to the brain). Because the body is evolved to associate ketosis with lack of food it would make no sense for it to make enough glycogen for the muscle, because there would be no sources of dietary protein, it would involve just stripping the muscles (overly quickly) for a role it's using fat for. And that would be bad from a survival perspective.

[u/chili_cold_blood → u/MeateatersRLosers]

It sounds like you think I'm advocating for a ketogenic diet. I'm not arguing in favor of any particular diet. I'm only arguing that diet affects metabolism, and more specifically that some diets seem to preserve or increase metabolic flexibility, while others reduce it.

In that sense, it would make no sense for humans to be "metabolically flexible" during normal times and burn fat in equal amounts.

This is incorrect because hunter-gatherers need to be able to continue to function well during brief periods when there isn't much food available, and metabolic flexibility helps with that. If you are very dependent on carbs, as with the HCLF group in the study I referred to, you're going to have a hard time if you can't get food for a few days and your body isn't prepared to burn body fat efficiently.

[u/ScipioLongstocking → u/mrlazyboy]

Despite caloric matching of discordant diets, we observed differences in body weight accumulation between diets, which appear to reflect changes in fat mass. This uncoupling between total energy consumed and body weight suggests that total caloric intake is not the sole determinant of body weight gain.

[u/Aeonoris → u/mrlazyboy]

The study discusses this! Here's an excerpt:

In the present study, many clinical parameters, including fat mass, LDL:HDL ratio, and markers of reproductive health, were differentially affected by adequate or excess energy intake, indicating that both caloric intake and the processed nature of the food are likely to contribute to the deleterious effect of UPF consumption.

Despite caloric matching of discordant diets, we observed differences in body weight accumulation between diets, which appear to reflect changes in fat mass. This uncoupling between total energy consumed and body weight suggests that total caloric intake is not the sole determinant of body weight gain.

And then, direct to your question:

Factors such as a decrease in the metabolizable energy available from unprocessed versus UPFs and/or alterations in metabolic rate caused by dietary-driven hormonal changes, such as GDF-15, could contribute to altered energy balance. Similarly, in a previous study, increased caloric intake driven by ultra-processed versus unprocessed diet did not fully account for the body weight increase. Based on the estimated relationship between caloric intake and body weight change, the total energy difference of 7,100 kcal between the ultra-processed and unprocessed diet consumption across the 2 weeks’ intervention was expected to lead to approximately 1 kg of weight gain, whereas study participants exhibited a difference in body weight of 1.8 kg across the intervention. Thus, the aggregation of this response to UPF in this latter study with our study provides evidence that calories from unprocessed or UPFs are not equally stored or metabolized, even when controlled for macronutrient load.

Emphases mine, and here's the link to the study

[u/aeneasaquinas → u/Aeonoris]

Despite caloric matching of discordant diets, we observed differences in body weight accumulation between diets

Sorry, does that mean they matched activity levels between people as well on the different diets? Matched caloric intake is meaningless without also matching that. Honest question, since I don't see that addressed.

Ed:

That study is incorrectly quoted.

Weight changes were highly correlated with energy intake (r = 0.8, p < 0.0001), with participants gaining 0.9 ± 0.3 kg (p = 0.009) during the ultra-processed diet

So uh, they did find 1kg. Not 1.8.

[u/Aeonoris → u/aeneasaquinas]

What they did was take the 43 participants, and randomly divide them into 2 groups, each with 2 subgroups.

Group 1.1 was given adequate calories of unprocessed food for three weeks, then given 12 weeks with no dietary intervention, then given adequate calories of ultra-processed food for 3 weeks. Group 1.2 was the same, but went in the reverse order (ultra>washout>un).

For groups 2.1 and 2.2 they did the same thing, except in each case the diets were of excess calories, rather than adequate calories. If you'd like details on what they mean by that, there's a link in the study.

For an overview of that methodology, the graphic Figure S1A (top one here: https://www.cell.com/cms/10.1016/j.cmet.2025.08.004/asset/aa0fddcb-0877-4889-ade2-f9e54860565a/main.assets/gr1_lrg.jpg ) is a great visual aid!

[u/Aeonoris → u/aeneasaquinas]

In response to your edit: Sorry, could you link where you're quoting that from? I'm having trouble finding it.

[u/aeneasaquinas → u/Aeonoris]

If you follow their citation for the 1.8kg excess, the article it links to does not agree with that.

[u/Aeonoris → u/aeneasaquinas]

As I said, I was having trouble finding it! I've got it though, and I'm wondering why you cut off the sentence:

Weight changes were highly correlated with energy intake (r = 0.8, p < 0.0001), with participants gaining 0.9 ± 0.3 kg (p = 0.009) during the ultra-processed diet and losing 0.9 ± 0.3 kg (p = 0.007) during the unprocessed diet.

https://www.sciencedirect.com/science/article/pii/S1550413119302487

So yes, there was a 1.8kg difference, exactly as the thread's study stated.

[u/aeneasaquinas → u/Aeonoris]

No, that is not right.

Yes, the DIFFERENCE is 1.8kg. But they stated that the increase in mass was expected to be 1, and was actually 1.8. That is incorrect - the change in mass is roughly the exact estimated amount.

[u/Aeonoris → u/aeneasaquinas]

[...] the total energy difference of 7,100 kcal between the ultra-processed and unprocessed diet consumption across the 2 weeks’ intervention was expected to lead to approximately 1 kg of weight gain, whereas study participants exhibited a difference in body weight of 1.8 kg across the intervention.

Maybe you take issue with their exact wording, but they are referring to the difference between the two groups throughout.

[u/memecut → u/aeneasaquinas]

Matching calories is easy, matching how much the individual burns naturally is impossible (we have tools to estimate, not know for sure, unless we measure daily for a very long time), and matching how much they burn through cardio is impossible as we have individual responses to fat burning.. on top of that there's muscle gain to account for..

So I kinda doubt they did.

[u/mrlazyboy → u/Aeonoris]

To be fair, the study had 9 participants and only lasted 1 week. There is so much noise in the data it’s not even worth drawing conclusions from.

To give you an example, my scale weight this week is up 6 pounds from last week. The only thing impacting my weight is I had a family bbq last Saturday and ate about 5k calories (my TDEE is about 2800).

My glycogen stores are full and I’m bloated like crazy. A small sample size + 1 week is irrelevant when you look at this kind of data.

If the researchers performed DEXA scans, at least they could start to draw conclusions about where the extra weight came from. I’d wager the experimental group would have a minor dip in BF% (due to water retention).

[u/Aeonoris → u/mrlazyboy]

To be fair, the study had 9 participants and only lasted 1 week. There is so much noise in the data it’s not even worth drawing conclusions from.

...What? Are you a chatbot just making up nonsense, or are you looking at a different study? If the latter, please link it.

The study we're talking about has N=43, and was 3-week diet A > 12-week washout > 3-week diet B, where A and B were randomly 'UPF' or 'unprocessed', split across the whole of N.

[u/LegLegend → u/mrlazyboy]

Ultra processed foods tend to make you hungrier or less full because they tend to be very high in sugar and lack fiber. You can eat whatever amount of twinkies or apples to reach the same calorie amount and stop there, but you're going to feel hungrier, emptier, more addicted, and worse if you just ate the twinkies. This usually lends to eating more later. There are some exceptions to this generalization, but they're not common.

[u/J4YD0G → u/LegLegend]

So it's sugar and not processed food?

Why work with the correlation when you can go to the cause right away.

[u/LegLegend → u/J4YD0G]

It's more than that.

What I've stated is just a broad generalization of ultra processed foods. High in sugar content and a lack of fiber are common in ultra processed foods but are not the only things that make them unhealthy.

For instance, ultra processed meats typically have a higher total of saturated fat content than unprocessed meats. This increase brings you closer to heart disease faster than if you were to just consume unprocessed red meats, and this isn't the only flaw with ultra processed meats.

Like the article here, a lot of research is still being done in the subject, but there is already a lot of confirmation out there that ultra processed foods aren't healthy for you. Sugar isn't the only concern.

[u/Acrobatic_Flamingo → u/LegLegend]

This all seems like it's pointing back to "A lot of foods that we all know are bad for you wind up ultra processed" rather than "there is something about processing food that makes it worse for you."

The danger here is, we've known what a healthy diet looks like for my entire life, but I keep seeing nutritional science essentially chase and reinforce fad diets that focus on one aspect of an unhealthy diet as the thing to worry about.

Focusing on process level is going to lead to people eating potato chips with "oil, potatoes, salt" as the ingredients and thinking they're healthy, in the same way the low fat diets of my youth increased sugar consumption and the more modern low-sugar diets lead people to excess fats.

[u/LegLegend → u/Acrobatic_Flamingo]

I think you're missing the point because generally all ultra-processed foods are bad for you. There are very rare exceptions, especially in bulk. The bigger issue here is the confusion around the term and what it means.

The fact that you mentioned potato chips goes into exactly what I'm talking about because that is an ultra-processed food. It goes through a long process of getting cut, dipped in oil, with added seasoning and preservatives. This is the definition of processed.

The foods you want are the foods that come right out of the ground, off the tree, or straight off the animal. That isn't to say there isn't risk to drinking milk right out of the cow, but those discussions are far less of a worry than the ultra-processed foods that are part of the everyday diet for most people in the United States.

[u/J4YD0G → u/LegLegend]

what about ultra processed meat alternatives? It's just a stupid categorization.

[u/LegLegend → u/J4YD0G]

It's not stupid at all, but I agree that it's very wide generalization. Ultra processed meat alternatives are healthier than ultra processed meat, but they're not going to be healthier than just eating the unprocessed versions of the vegetables used to make them.

I think the problem here is that people don't understand the descriptor. Ultra processed means it's gone through a heavy process to reach the final result. Oils, salts, sugars, and preservatives are all added to these foods and the more processed it is, the more of those things are used on it. Those things are not healthy for you.

To summarize for you, the closer food is to its original source, the healthier it is for you. Yes, there are still risks to drinking milk right out of the cow (drinking milk is a whole other discussion), but ultra processed foods are a prime piece of nearly every American's diet. It is a big concern.

Again, there are exceptions. Yogurt is a processed food that tends to be quite healthy for you. However, these exceptions are rare. There is no realm where McDonald's fries are healthier than just eating a raw (if your digestive tract can handle it) or baked potato.

[u/not_today_thank → u/mrlazyboy]

First of all people in general aren't very good at balancing calories in a deliberate manner, especially if they have eaten a lot of calories and are still hungry. It only takes an imbalance of 10 calories per day to gain (or lose) 10.4 pounds in a decade. Our bodies actually seem pretty good about balancing calories on its own without our help. But throw in an ingredient that tricks your body into wanting more and it isn't hard for weight gain to get out of control. People don't usually get fat over-night, they usually only gain like 1-5 pounds a year, so we're talking 10-50 extra calories a day on average. Going from 150 pounds at age 20 to 200 pounds at age 50, is only an extra 16 calories a day.

Secondly, there have been rat studies that have demonstrated rats fed the same number of calories from different ingredients have gained signficantly different amounts of weight. There very likely is a difference in how much weight you will or won't gain depending on where those 2800 calories come from. Like from this study:

Despite caloric matching of discordant diets, we observed differences in body weight accumulation between diets, which appear to reflect changes in fat mass. This uncoupling between total energy consumed and body weight suggests that total caloric intake is not the sole determinant of body weight gain.

[u/mrlazyboy → u/not_today_thank]

Note the researchers last sentence mentioned body weight gain. They didn’t make any statement about tissue which is way more important.

If somebody consistently eats 3k calories of bananas and the other rats 3k calories of pizza for a whole month, their body weights will really start to diverge.

Pizza has more salt (water retention) but also more calorically dense (less semi-digested food in your body). Pizza might make you constipated (more semi-digested food). There are so many variables, these studies need to actually look at good measures of body composition.

Imagine the only difference between those 2 people in terms of body weight was water retention. We would be drawing conclusions from… nothing.

[u/jmlinden7 → u/mrlazyboy]

They taste too good and make it easier to overeat

[u/Uncool_runnings → u/mrlazyboy]

There are numerous studies now suggesting ultra processed foods lead you to over eat, in a way that whole foods don't.

The human bodies entire eating self-regulatory system is bypassed for these food groups.

[u/mrlazyboy → u/Uncool_runnings]

So what you’re saying is eating more calories of UPF makes you gain more weight than eating fewer calories of healthy food?

Do you think this is a novel statement? That eating more food makes you gain more weight?

This is what the argument always boils down to: UPF makes you hungry (it does!) so it makes you eat more of it, so you gain weight.

What you actually need is a longer-term study (probably at least 1 month, ideally 2-3) with 50-100 people all verifiably eating their TDEE every day. Then break them into 2 groups: UPF and healthy foods. Then see what happens to their scale weight but also body composition.

[u/Uncool_runnings → u/mrlazyboy]

I'm pretty sure we fully agree with each other here.

[u/Silverfrost_01 → u/mrlazyboy]

Most ultra processed foods that the average person eats is mostly things like McDonald’s, which is just not going to satiate hunger. Eating all of your calories in sugar vs other macronutrients may result in similar body mass, but definitely very different body composition over long periods of time.

[u/isotope123 → u/mrlazyboy]

Ultra processed foods tend to be higher calorically (or designed to make you want to eat more than you should (sugar, salt, etc.)). It is "easier" to gain weight eating nothing but McDonalds, because you can easily eat more McDonalds than you should. Tracking your calories helps eliminate this issue.

[u/womerah → u/mrlazyboy]

You need to have a more holistic, systems-based view of a human being.

Imagine there is an evil mandarin. It has 40 calories, but eating one a day gives you extreme depression while making you extremely hungry. Adding this evil mandarin to your diet will cause you to gain large amounts of weight while destroying your quality of life.

What you're saying is akin to saying that this evil mandarin is actually OK to eat as long as you don't exceed your TDEE. You're technically correct but you're completely missing the point of the discussion around ultraprocessed foods IMO.

If you want to keep the discussion in terms of calories and TDEE, then the framing is to not consider TDEE static - but TDEE itself being a function of your diet. So they are interlinked, your diet impacts your TDEE, and your TDEE in turn impacts your diet. Snake eating it's own tail sort of situation.

[u/Master_Income_8991 → u/mrlazyboy]

That is exactly what this study is about, they controlled for calorie intake and found that UPFs make you fatter independent of calories intake.

As for whey protein, I think that can probably be dismissed as an outlier since it is but one of the thousands of possible UPF choices. I'm sure some people in the UPF group did consume whey protein in some form and the influence on the data was overwhelmed by other people eating UPFs that weren't whey protein. The wonders of statistics and all that.

[u/xakeri → u/mrlazyboy]

Ultraprocessed foods are made to make you eat more of them. They're literally designed in a lab to make people want to gorge themselves. They taste better, are less filling, and lead people to overeat.

Edit: I guess I didn't bring it back around to the TDEE. That's correct. 2800 calories of Twinkies is the same as 2800 calories of broccoli, rice, and chicken. But that's 20 Twinkies.

Compare it to the broccoli, rice, and chicken. 2 tbsp of olive oil is 240 calories. 100 grams of broccoli is 34 calories. 100 grams of rice is 130 calories. 100 grams of chicken breast is 165 calories. To get to 2800 calories of chicken, rice, and broccoli, using oil to cook the chicken and broccoli, you need to eat so much more. It is more filling. It isn't designed in a lab to be addicting.

Saying the food isn't the issue is missing the forest for the trees. Yeah, people can eat 20 Twinkies a day for their 2800 calories, but that's only if they can stop at 20 Twinkies and eat nothing else. Given the high rates of obesity and all the studies linking it to ultraprocessed foods, it looks like the vast majority of people can't.

[u/reddit_reaper → u/xakeri]

Ok but the food itself isn't the issue. They do this with everything and it's why there's sugar in so many foods

[u/AnyJamesBookerFans → u/reddit_reaper]

The food is the issue. That’s what this study looked at. Same calories in from different diets lead to different health outcomes!

[u/XXLpeanuts → u/reddit_reaper]

Yup, and people need to know the reason these foods exist and how they are making them form bad habits and gain weight etc. So what exactly is your objection to studies like this?