100: Does Intermittent Fasting Actually Work in 2026?

 This week on Tasty Tip, we break down three new health stories:
 • What new research says about intermittent fasting and metabolic health
 • Why early-onset colon cancer rates are rising
 • Whether caffeine intake may reduce dementia risk 

Transcript

New Format: Three Health Stories

SPEAKER_01 0:01

Hi, welcome to your checkup. We are the Patient Education Podcast, where we bring conversation from the doctor's office to your ears. On this podcast, we try to bring medicine closer to its patients. I'm Ed Delesky, a family medicine doctor in the Philadelphia area.

SPEAKER_00 0:15

And I'm Paul Ruffel, I'm a nurse.

SPEAKER_01 0:17

And we are so excited you were able to join us here again today. So there was, I was trying to do something where we were really great at our once-a-week episodes. And I like them to normally be focused on one particular topic. But I've been finding this thing where I can find a lot of news, health-related news things. So we're going to record this and see if it's going to stick. Or we choose three stories and we just do a quick little recap of the story, little impression, and then we move on. What do you think, Nick?

SPEAKER_00 0:54

I think that sounds great.

Intermittent Fasting Under The Microscope

SPEAKER_01 0:55

Okay, great. So I'll give it to you this way. This article I have here is intermittent fasting offers no significant advantage over standard weight loss advice. This is from a Cochrane review that found minimal impact on weight, quality of life, and metabolic outcomes. So it's a trendy diet that's captivated millions of Americans. And it's some have said in this research that it may not be better than conventional weight loss advice. There is a comprehensive review published in February 16th, 2026, in the Cochrane database of systematic reviews, finding that intermittent fasting produces little to no meaningful difference in weight loss or quality of life compared to standard dietary guidance. So there was an evidence gap. The Cochrane Review was led by researchers and they analyzed 22 studies involving nearly 2,000 adults across North America, Europe, China, Australia, and South America. When compared to regular dietary advice, the intermittent fasting showed no clinically significant advantage for weight loss with a mean difference of just 0.33% in baseline weight. Quality of life measures were similarly unimpressive, showing no meaningful improvement. So the findings challenge the explosive popularity of intermittent fasting, which has been heavily promoted across the internet and otherwise. The biological mechanisms sound promising, but the real-world results tell a different story. So there are some methodological concerns with the studies. The authors, the reviewers, highlighted a critical weakness that most studies analyzed and used questionable methods and enrolled small numbers of participants, making it difficult to determine intermittent fasting's true effects. The evidence quality ranged from low to very low certainty for most outcomes, including adverse events. Notably, none of the included studies examined participant satisfaction, diabetes status, or overall comorbidity measures, leaving major knowledge gaps. All the studies focused on short-term effects up to 12 months, limiting their applicability for long-term weight management. And the authors therefore concluded that physicians and patients should carefully evaluate the practicality and sustainability of intermittent fasting on an individual basis rather than embracing it as a universal solution. So the thing with research is that it's meant for broad swaths and populations of people, and that's what is studied. And I think it's fair to say that what works for one person might not work for another. And I've heard that this can be a healthy mechanism. And I've also, I think we go back and forth over the years, like probably a couple years from now and a couple years before this, there was an intermittent fasting article that came out saying that it might be helpful. And so this is how this goes. Um, people look into things and they find different results when they look at it from different ways, and that's what makes science challenging. If it's something you're interested in trying, you can. Or you talk to your clinician about it. But that's what I read. What impressions do you have?

SPEAKER_00 4:23

Well, it's interesting because it's like you said, it's kind of like a fad diet. So it's very heavy on the internet right now of the intermittent fasting community. Oh, really? And everyone who swears by it.

SPEAKER_01 4:34

Oh.

SPEAKER_00 4:36

And I feel like it's hard to do long term. I tried it. Like I just like kind of wanted to see what all the hype was about.

SPEAKER_01 4:49

Yeah.

Hormones, Hunger, And Morning Meals

SPEAKER_00 4:50

And I feel like you're just like eating one less meal during the day. So that's why you're losing weight.

SPEAKER_01 5:01

You are capturing that calorie deficit.

SPEAKER_00 5:04

Yeah.

SPEAKER_01 5:05

Through some sort of like structured mechanism. I find it interesting because we know like there are three hormones that people blame for weight gain, and they you know usually are named cortisol, estrogen, and thyroid hormones. And then when people are like, oh my god, my hormones are off, I in part agree with them, but then explain that it's not any hormone they've likely ever heard before. So when I say hormones, I mean like ghrelin.

SPEAKER_00 5:34

Yeah.

SPEAKER_01 5:34

And that ghrelin being the one of the main hunger hormones released from the stomach is increased a lot. And what we know is that when people eat more in the morning and they have food earlier in the day, they are less likely to become hyperphagic or my just dropped hyperphagic, um, super, super hungry and eat more later in the day. So thanks for giving your two cents there.

SPEAKER_00 6:05

Oh, you're welcome.

SPEAKER_01 6:06

I got another one for us.

SPEAKER_00 6:08

Another one.

Early-Onset Colon Cancer Alarms

SPEAKER_01 6:09

Yeah. Scary one. Early onset, colorectal cancer rising. Alarming trends in younger adults. There is an incidence climbing globally with the highest increases in adults under 40, despite screening advances.

SPEAKER_00 6:27

What are the screening advances?

SPEAKER_01 6:29

Recently, the screening advances in the last five years were from age 50 to 45. Or 10 years before the first family member was diagnosed, or 40, whichever comes sooner for people with family histories. But from 50 to 45 was the across the board one.

SPEAKER_00 6:50

Oh. Yeah. I've been seeing this a lot too.

SPEAKER_01 6:58

So there was a JAMA review in 2025 assessing that early onset colorectal cancer, classifying as a diagnosis before the age of 50, now represents 14% of all cases in the United States, with incidence rates climbing. That's incidence is like the rate of which a new disease is discovered. Incidence rates climbing approximately 2% annually since the mid-1990s. And more troubling still, the steepest increases are occurring in adults under 40, where rates jumped from 4.1 to 5.5 per 100,000 between 2013 and 2022. The rise stands in stark contrast to declining rates among older adults who benefit from widespread screening programs. There was another article in a 2025 Lancet Oncology analysis of 50 countries found that 27 nations now show increased early onset colorectal cancer rates, with the trend either exclusive to younger adults or accelerating faster than in older populations. The United States, Australia, New Zealand, and multiple European nations are experiencing annual increases of 2 to 4%. The cause remains frustratingly elusive. We're not going to make any groundbreaking statements here. While 16 to 35% of early onset cases involve hereditary syndromes, things like Lynch syndrome, most are sporadic. A 2022 New England Journal of Medicine review identified Western diet patterns. We're going to talk about this in a few weeks. Western dietary patterns, sugar-sweetened beverages, obesity, and sedentary behavior as key modifiable risk factors. That's huge. Wow. Women consuming two or more daily servings of sugar-sweetened beverages faced double the risk. Double the risk compared to those drinking less than one serving weekly. Hold on. Wait. Women consuming two or more daily servings of sugar-sweetened beverages faced double the risk compared to those drinking less than one weekly. Okay. Each additional daily serving during adolescence increased risk by 32%. Wow.

SPEAKER_00 9:36

Oh my God.

SPEAKER_01 9:38

I actually was thinking about this a lot because bad news for you.

SPEAKER_00 9:42

What?

SPEAKER_01 9:42

Oh.

SPEAKER_00 9:43

Your Mountain Dew in your childhood.

SPEAKER_01 9:45

Oh my God. No. That fateful night. Once a year. Well, I've been thinking about this a lot. Well, hold on. We'll get to our thing. The NCCN now recommends genetic counseling for all patients diagnosed before age 50. The American Cancer Society lowered its screening recommendation to age 45 in 2019. That was close. Yet cases continue rising most rapidly in those under 40, suggesting screening alone cannot solve this crisis.

SPEAKER_00 10:22

Perfect.

Risk Factors And Screening Gaps

SPEAKER_01 10:23

Wow. Sugar sweetened beverages. I had been thinking about these a lot because I, in addition to making a podcast, I am a nerd who also listens to a lot of them. And I forget which ones specifically, but it was about like teen, it was about like pediatric obesity and going after the sugar-sweetened beverages and how to like talk to families about this. And if I I started hunting a little bit more in my visits, looking for like how many sugar-sweetened beverages do you have? And I've this is a very new thing, so it's about four in adolescent patients. And I'm like three for four on teens having like soda or other sugar-sweetened beverages.

SPEAKER_00 11:07

Oh my goodness.

SPEAKER_01 11:11

What what are this? Um what do you think about this? You've been seeing this online too?

SPEAKER_00 11:18

Yeah, I keep getting served. Oh my god, these TikToks. I don't know why, because I don't ask for it. Of like these people who are like 35 and they're like, I just got diagnosed with stage three colon cancer. These were the symptoms I have, and it's like diarrhea, and I'm like, oh, sick.

SPEAKER_01 11:37

Yeah. No, it's awful. Um, I think personally, my threshold. Well, here's the thing. I think far too many. This is actually terrifying because a lot of people come in with GI concerns, you know, and they're like, oh, I need to.

SPEAKER_00 11:57

I feel like even any GI problem that's not cancer is alright, can already be so hard to diagnose because there's like so much going on. I agree. It could be like a million things at any given time.

SPEAKER_01 12:10

It could be, and I think far too often people get slapped with a diagnosis of irritable bowel syndrome from getting sized up. Like they get the once over, you they get talked to, not much else happens, and then they get the irritable bowel syndrome diagnosis. And I feel like that's not good enough anymore. I don't know if it was ever good enough. Like as a new attending, my after hearing these stories, and then like some of them sensational for sure, being online, but like, and if it if it quacks and it waddles and it flies, it's a duck. And the same goes for irritable bowel syndrome, but but it's a diagnosis of exclusion. And so, like, you need all the testing to be done, probably including a colonoscopy. After reading this, I think I'm gonna have a lot more people go see GI.

SPEAKER_00 13:11

I think I'm gonna go get a colonoscopy.

SPEAKER_01 13:14

Well, I even had a guy come in who was like totally healthy, and he was like, I want a colonoscopy, and he was early 40s, and I was like, Do you have a family history? He's like, No, but I want it and I need to be here for my family.

SPEAKER_00 13:26

And I was like, Cool, sounds good, and he paid for it, and it was fine, but like listen, if they asks, if they asks your parents and all of your siblings. What's that? He said, if anyone asks your parents and all of your siblings have colorectal cancer and you need a colonoscopy. Good point.

SPEAKER_01 13:46

Yeah, I guess you could um just kidding.

SPEAKER_00 13:48

I didn't say that out loud.

SPEAKER_01 13:49

No, you wouldn't imply fraud.

SPEAKER_00 13:51

No, never. Well, I guess I'm gonna really anchor myself to the fact that my mom never let us drink soda growing up.

SPEAKER_01 14:00

This sugar sweet.

SPEAKER_00 14:01

And therefore, none of us ever developed a taste for it. So no sugar sweetened beverages for the Arufos.

SPEAKER_01 14:07

That's my big takeaway from this. The sugar sweetened beverage risk factor. And we do know that um obesity is a risk factor for several cancers. Like as many as 13, perhaps, maybe more. And that risk persists. So that is also an interesting thing. For a disease once considered rare in younger adults, it's becoming the leading or second leading cause of cancer death.

SPEAKER_00 14:40

Perfect.

SPEAKER_01 14:42

Yeah, excellent stuff. Sorry to hit you guys with that. Um, not the best news at all. Let's see what else I got here. Is there anything more possible?

SPEAKER_00 14:56

More positive?

SPEAKER_01 14:57

More positive. Oh, this one looks good. Oh, thank God. Here we go. Moderate caffeine intake linked to lower dementia risk in long-term study.

SPEAKER_00 15:08

Oh, what's moderate?

SPEAKER_01 15:09

A study of 130,000 Americans finds that two to three cups daily may protect cognitive function.

SPEAKER_00 15:17

Look at us.

SPEAKER_01 15:18

Here we go. Your morning coffee habit may be doing more than keeping you alert. A major study tracking over 130,000 Americans for up to 43 years. Wow. 43 has found that moderate caffeine consumption is associated. Okay, careful. The word associated does not mean cause, but is associated with substantially reduced risk of dementia. And this was reported in JAMA on February 9th, 2015.

SPEAKER_00 15:50

Our bowels will be trying to kill us, but we won't be confused while it's happening.

SPEAKER_01 16:10

The research which followed Oh, geez.

SPEAKER_00 16:14

The black lobby.

Soda, Teens, And Real-World Clinic Notes

SPEAKER_01 16:20

The research which followed participants in the nurse's health study, good job.

SPEAKER_00 16:25

Thanks.

SPEAKER_01 16:26

And health professionals' follow-up study revealed a striking dose response relationship. Those who consumed two to three cups of caffeinated coffee daily showed an 18% risk lowered of developing dementia compared to non-drinkers. Tea drinkers saw similar benefits at one to two cups per day. And crucially, more wasn't better. The protective effect plateaued at moderate intake levels with no additional benefit from higher consumption. The findings held up regardless of genetic factors, including the ApoE4 gene variant that dramatically increases Alzheimer's disease susceptibility, and decaffeinated coffee showed no significant protective effect, suggesting that caffeine itself plays a role. So there are theories about why caffeine protects the brain, and the mechanism appears complicated, of course. Caffeine blocks adenosine receptors in the brain, which may reduce accumulation of amyloid beta blacks. It's a hallmark of Alzheimer's disease. Laboratory studies suggest it also enhances neuronal plasticity, which is the oh, como se dice, um how well the neurons actually fire and link up with each other when people learn things. And boosts mitochondrial function, the powerhouse of the cell, and dampens neuroinflammation. Damn neuroinflammation. Coffee and tea's polyphenols add antioxidant and vascular benefits that may further protect against cognitive decline. I would really love to know if this would this study was funded by big coffee. By Folgers. Every every what is it their thing? Every cup. Do do the best part of waking up is Folgers. Is it cup of Folgers? Yeah. Not waking up next to the woman you love. The protective associations extended beyond the dementia diagnosis. Moderate caffeine consumers reported less subjective cognitive decline and performed modestly better on modestly on objective cognitive tests. The benefits were particularly pronounced in participants aged 75 and younger, suggesting earlier intervention may matter most. With Alzheimer's disease projected to affect 13 million Americans by 2050, and limited treatment options available, these findings offer a rare piece of good news, which is how we're happy to leave you here today. A simple, widely accessible dietary habit that may pres help preserve cognitive function. I think that's good news. I think it's a I don't know how. I don't know. I actually it's more rare when I meet someone and they're like, I don't drink coffee, period.

SPEAKER_00 19:51

Yeah, I agree.

SPEAKER_01 19:53

Um please give me your thoughts on what you heard here.

SPEAKER_00 19:59

About the coffee. I like it. Gonna keep drinking coffee. Remember when I went to a neurologist one time and was talking about my headaches? I feel like he was judging me because he asked if I drink coffee and how much coffee I drink. And I feel like he was a little bit like, you're a big dumb idiot. You have headaches because you drink coffee.

SPEAKER_01 20:26

Was that recently?

SPEAKER_00 20:28

That was when I went like a year or so ago.

SPEAKER_01 20:30

Oh, at that.

SPEAKER_00 20:31

Oh. No.

IBS, Misdiagnosis, And When To Scope

SPEAKER_01 20:35

No. Look, I if this is true, great. If it's not, I'm still gonna keep drinking coffee. And I think anyone who's not doing like not ripping eight to ten cups of coffee a day, it's probably fine. And just huzzah for coffee at the end of the day.

SPEAKER_00 20:59

Huzzah. Put down the soda, drink coffee.

SPEAKER_01 21:02

Yeah, put down the sugar sweetened beverages. Geez. Not good. So thank you for coming back to another episode of Your Checkup. Hopefully, you were able to learn something for yourself, a loved one, or a neighbor. You can find us on Threads, you can find us on Instagram, and hopefully you like this little bit of a new format that we're gonna squeeze in here every once in a while. But most importantly, stay healthy, my friends. Until next time, I'm Ed Deleski.

SPEAKER_00 21:30

I'm Nicole Arufo.

SPEAKER_01 21:31

Thank you and goodbye.

SPEAKER_00 21:33

Bye.

SPEAKER_01 21:38

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