There’s no shortage of health advice these days.
Scroll long enough and you’ll find someone selling you the next “miracle” diet, detox, or anti-ageing protocol, usually backed by “vibes”, not science.
Books are no different.
Walk into a bookstore and you’ll see shelf after shelf of titles promising to fix your metabolism, reverse disease, or make you live to 120.
But here’s the problem: most of them are all theory and no substance.
Some sound smart, but fall apart when you actually try their advice.
Some are built on cherry-picked studies.
And some are just recycled blog posts with a hardcover.
So we decided to do something different.
We went looking for books that are actually backed by science.
Books that explain things clearly, don’t overpromise, and hold up when you look under the hood.
To help with that, we used Red Pen Reviews - a platform that breaks down health and nutrition books based on how accurate, evidence-based, and useful they actually are.
Here are five books that passed the test -and what you need to know before reading them.
Make sure you check all the 5, as the last one will surprise you.
1. Outlive by Peter Attia
This one’s for people who don’t just want to live longer,
but actually want to feel better as they age. (See what this means and how to achieve healthy longevity here)
Attia breaks down the stuff that really matters over the long term - blood sugar, muscle loss, heart health, cognitive decline and explains how they all connect.
He’s not offering shortcuts or hacks, just helping you understand where to pay attention, and what to get ahead of now so you’re not caught off guard later.
It has an overall score of 78% with an accuracy score of 83%
It’s not light reading though, and not everything may feel immediately relevant.
But if you’re serious about healthy ageing, there’s a lot in here that’s worth sitting with.
2. The Obesity Code by Jason Fung
This book made a big splash when it came out and for good reason.
Fung challenges the usual “eat less, move more” logic, arguing that high insulin levels, not just calories, are the main driver of weight gain.
His solution is centered around cutting carbs and introducing intermittent fasting.
The core ideas are compelling, especially for anyone struggling with fat loss despite doing “everything right.”
And to be fair, the actual diet recommendations - cutting added sugar, refined grains, and processed food are generally sound.
But the science isn’t always as strong as the story.
Red Pen Reviews gave this one a low score on scientific accuracy,
mostly because of overstatements around calories not causing weight loss, and the idea that insulin is the “PRIMARY” cause of obesity…
something not well supported by current research.
That said, if you’re curious about fasting, or want a new lens on insulin resistance and metabolic health, there’s still value here.
Just read it with your critical filter on, and don’t take everything word for word
3. Eat, Drink, and Be Healthy by Walter Willett
If you’ve ever wanted a clear, science-first breakdown of what a healthy diet actually looks like without gimmicks, this would be a good one.
Walter Willett (of Harvard Medical School and the Nurses’ Health Study) brings decades of nutrition research into a book that focuses on long-term health, not trends.
Red Pen Reviews gave this one some of the highest scores they’ve ever given: 97% overall, with a perfect score on healthfulness.
No dramatic claims.
No restrictive rules. Just well-supported guidance that can be adapted to most diets and lifestyles.
The advice is simple - more fruits, vegetables, whole grains, healthy fats, and lean protein.
Less added sugar, and refined carbs.
And yes, there’s nuance around things like dairy, fat, and multivitamins.
If you want clarity without the complexity, this is a smart, low-friction place to start.
4. The Good Gut by Justin and Erica Sonnenburg
Gut health is one of those topics everyone seems to talk about…
but most of what you hear online is either oversimplified or overhyped.
The Good Gut cuts through that mess.
It’s written by Justin and Erica Sonnenburg, two researchers who actually work in the field,
And it walks you through how your gut bacteria impact your immune system, digestion, even your mood, and why modern life is rough on that system.
The advice isn’t complicated: more fiber, more fermented foods, fewer unnecessary antibiotics, and a little more contact with nature.
The science backing the immune side of things is strong.
The claims about weight and gut health are a little less clear, but even then, the basic diet and lifestyle shifts they recommend are solid for anyone trying to achieve healthy longevity
Red Pen Reviews gave it an overall score of 86%, with especially strong marks for scientific accuracy, reference use, and healthfulness.
And the best part is, it’s actually readable. No scare tactics. No miracle cures. Just useful ways to make your gut a lot harder to mess up.
If you’re serious about building health from the inside out, this one’s worth your time.
5.
The Longevity Diet by Valter Longo
We saved this one for last, because when it comes to healthfulness, it scored a rare 100% from Red Pen Reviews.
And in a world full of extreme diets and sketchy advice, that’s worth paying attention to.
The Longevity Diet takes a big question that The Oak Age answers.
“How do you not just live longer, but stay healthier as you age”,
and builds a clear answer around it.
It has a very structured approach to eating fewer meals and using something called a “fasting-mimicking diet” to tap into your body’s repair systems.
The book isn’t perfect.
Some claims about cutting protein very low or eliminating animal foods completely are less well-supported than others.
And the fasting-mimicking diet kit Longo promotes isn’t cheap.
But if you’re serious about learning how to slow down ageing from a nutrition and lifestyle standpoint, this is one of the better guides out there.
You don’t have to follow it 100% to benefit.
You don’t have to eliminate everything or starve yourself.
But understanding the core ideas,
how cellular repair works, why time-restricted eating matters, and what real longevity habits look like, can give you tools most people never even hear about.
If you want a clear, science-grounded look at how food shapes your future health, The Longevity Diet is worth adding to your stack.
Let’s Close…
The internet is full of advice about healthy ageing.
Some of it’s extremely helpful and might be the ONE thing you need. .
But most of it just makes people more confused, or worse, sends them chasing ideas that don’t work.
That’s why we put together lists like this.
Not to sell you miracle cures or fad diets or some random gimmicks with 1 clinical study that’s also inconclusive .
But to point you toward the ideas, books, research, and habits that actually hold up when you look deeper.
If you want more straight-shooting breakdowns like this.., and understand how to slow down ageing and improve healthy longevity,
you’ll want to be on our free email list.
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