Sugar and Inflammation: The Advice I Give Every Patient
What the Science Really Says
The science says a lot of things. Too many things, honestly. And in the field of nutrition especially, it has a complicated relationship with the truth — shaped by industry funding, flawed study designs, and headlines that reverse themselves so often it's become a running joke. Eggs are bad. Eggs are fine. Fat is the enemy. Fat is back. Coffee will kill you. Coffee will save you.
It's enough to make you give up entirely — which, arguably, is part of the problem.
The amount of health information available today is not just overwhelming, it's almost paralyzing, really. And it comes at you from every direction — nootropics, mushrooms, adaptogens, collagen, eat meat, don't eat meat, take supplements, don't bother. The wellness industry never stops talking, and social media feeds are happy to amplify every new trend the moment it emerges. Although I'm unabashedly a sucker for wearable devices. 😳
And while we're at it, can we retire "everything in moderation"? I understand the spirit of it, but it doesn't hold up. Nobody sensible is suggesting you drink Coca-Cola in moderation or eat Cheetos in moderation as a daily strategy — and honestly, I'm not even sure Cheetos should exist. Not because I'm a killjoy, but because there is a category of food-like product out there — the neon, the artificially flavored, the things engineered specifically to make a child lose their mind in a convenience store — that has no real business being in a food system at all. We eat it because it tastes good. That's the whole design. And the food industry is very, very good at their job.
Now, if you're craving a cold Coke on a hot day a few times a year, or you find yourself at the bottom of a bag of Cheetos on a road trip — that's life, and it's fun, and it has nothing to do with moderation as a philosophy. The word implies all things are roughly equal and just need to be rationed. They're not.
But buried inside all of that noise, there are signals that have held up — findings that don't reverse with the next study, that show up consistently across completely different disease models, that major health organizations keep coming back to decade after decade. One of them isn't hiding in some obscure corner of the research. It's sitting right there on the nutrition label of foods you're probably eating every single day.
Reduce your added sugar intake as much as you reasonably can.
Not because it's trending. Not because some wellness influencer said so. Because added and refined sugar is among the rare dietary variables where the science has remained remarkably consistent, year after year — across cardiovascular disease, metabolic dysfunction, autoimmune conditions, and even mood disorders.
What Makes Sugar Different
Nutrition science is famously contentious — and not just for the reasons we've already touched on. Meat or no meat. Saturated fat: villain or misunderstood? Coffee: harmful or beneficial? Eggs, salt, dairy, gluten — the list of dietary debates is long, and reasonable scientists genuinely disagree on most of them. That's not a flaw in the science; it reflects the real complexity of human biology and the difficulty of studying diet in free-living people over long periods of time.
Sugar, however, has accumulated a different kind of evidence base.
In April of 2023, The BMJ — one of the world's most respected and widely read medical journals — published what may be the most comprehensive analysis of sugar and human health ever conducted. It was an umbrella review, meaning it reviewed 73 existing meta-analyses, which themselves synthesized thousands of individual studies, covering 83 distinct health outcomes. The findings were striking: significant harmful associations were found between dietary sugar consumption and 18 endocrine and metabolic outcomes, 10 cardiovascular outcomes, and 7 cancer outcomes. The authors recommended reducing free and added sugar intake to below 25 grams per day (roughly 6 teaspoons) and limiting sugar-sweetened beverages to fewer than one serving per week.
An umbrella review of 73 meta-analyses is, in the hierarchy of medical evidence, about as high as it gets. This isn't one study. It's a synthesis of the synthesis of thousands of studies. And the conclusion was clear.
This doesn't mean every question about sugar has been settled — science doesn't work that way. But it does mean that the weight of evidence against excess added sugar is unusually robust, especially when compared to the ongoing debates about most other individual dietary components.
Sugar and Inflammation: The Biological Connection
One of the central mechanisms through which excess sugar does its damage is inflammation — specifically, the kind of chronic, low-grade inflammation that doesn't announce itself with obvious symptoms, but quietly drives disease processes over years and decades.
Chronic inflammation is now recognized as a shared feature across most of the serious diseases of modern life — heart disease, type 2 diabetes, metabolic syndrome, many autoimmune conditions, and increasingly, mood and cognitive disorders. It isn't the sole cause of any of them, and inflammation itself isn't the enemy; it's an essential part of how the body heals. The problem is when it becomes chronic and low-grade, quietly persistent in the background, driven by the kind of lifestyle and dietary patterns that have become normalized in industrialized societies. And among the most significant dietary contributors to that inflammatory burden — alongside trans fats, refined carbohydrates, and ultra-processed foods — excess added sugar, particularly from refined sources and sweetened beverages, stands out for the consistency and breadth of evidence against it.
Here's how it works, in broad terms. When you consume large amounts of added sugar, blood glucose rises rapidly, triggering an insulin response and stimulating the release of pro-inflammatory signaling molecules called cytokines. Over time, repeated sugar-driven spikes contribute to a state of chronic low-grade inflammation, measurable through specific markers in the blood:
CRP (C-reactive protein): A general marker of systemic inflammation, elevated in metabolic syndrome and cardiovascular disease. Sugar intake, particularly from sweetened drinks, raises CRP levels.
IL-6 (Interleukin-6): A cytokine elevated in obesity, insulin resistance, and chronic disease. Regular sugar consumption is associated with increased IL-6, especially in individuals with higher amounts of visceral fat.
TNF-α (Tumor Necrosis Factor-alpha): A pro-inflammatory cytokine involved in chronic pain and metabolic dysfunction, which can be elevated by high sugar intake, particularly in combination with processed or high-fat foods.
IL-1β (Interleukin-1 beta): Drives insulin resistance and systemic inflammation. Diets high in sugar, especially fructose, can increase IL-1β activity in fat tissue and the gut.
Reducing or eliminating added sugars has been shown to produce measurable drops in these markers — which is part of why, as a physical therapist working with patients who live with chronic inflammation, this is consistently the first dietary change I recommend. It's not the only lever worth pulling, but it's the most evidence-based and, for many people, the most impactful place to start.
But What Is Sugar, Really?
One of the most common questions I hear is: "But what counts as sugar?" And honestly, that question tells us something important about how deeply sugar has been normalized, and disguised, in our food system.
It's not just the white granules in the sugar bowl. Sugar appears in dozens of forms on ingredient labels, many of them designed to sound benign, natural, or even healthy. Learning to recognize them is one of the most practical steps you can take. Here are some of the most common names for added sugar to look for:
Cane sugar
Brown sugar
High-fructose corn syrup (it should be banned IMHO)
Agave nectar
Honey
Maple syrup
Molasses
Fruit juice concentrate
Malt syrup or barley malt
Brown rice syrup
Dextrose, glucose, fructose, maltose, sucrose, lactose
Turbinado or "raw" sugar
Invert sugar (what?)
Corn syrup solids (yuck!)
Coconut sugar
A note on a few of these: honey, maple syrup, and coconut sugar are often marketed as healthier alternatives. They do contain trace minerals and have slightly different glycemic profiles, but in the context of inflammatory load and blood sugar response, the body processes them in broadly similar ways to refined sugar. Small amounts — a drizzle of honey, a splash of maple syrup — are unlikely to be the problem. It's the cumulative daily total that matters.
Are All Sugars the Same?
No — and this distinction matters. The concern here is primarily with added and refined sugars: those that have been extracted, concentrated, and incorporated into processed foods and drinks, stripped of the fiber, antioxidants, and micronutrients that would otherwise accompany them.
Whole, unprocessed foods that naturally contain sugar tell a different story. Whole fruit, for example, comes packaged with fiber, water, vitamins, and phytochemicals that slow sugar absorption and reduce its inflammatory impact. Some fruits are particularly well-suited for people managing inflammation:
Berries (strawberries, raspberries, blackberries) — low in sugar, high in antioxidants
Kiwi — modest sugar content with notable anti-inflammatory properties
Avocado — technically a fruit, and very low in sugar
Lemons and limes — minimal sugar, and useful as flavor enhancers that can replace sweetened dressings and sauces
Starchy vegetables like sweet potatoes and winter squash also provide natural sugars alongside meaningful nutrition. And small amounts of minimally processed sweeteners — a date, a little honey paired with protein or fiber — can be tolerated by most people without significant inflammatory effect.
Dark chocolate at 70% cacao or higher is worth a mention too: the flavonoids it contains may actually have mild anti-inflammatory effects when consumed in moderation.
The practical takeaway is this: nature's packaging matters. Sugar embedded in a whole food, surrounded by fiber and nutrients, behaves very differently in the body than sugar extracted and added to a processed product.
Where Sugar Hides
Beyond the obvious offenders — sodas, candy, pastries — sugar turns up in foods that are frequently marketed as healthy choices:
Condiments and sauces. Ketchup, barbecue sauce, teriyaki sauce, and many salad dressings are surprisingly high in added sugar. It adds up quickly across a meal.
Breakfast cereals and granola bars. Even products labeled "natural," "organic," or "whole grain" can be significant sources of added sugar. Reading the label is the only reliable way to know.
Energy and sports drinks. High in sugar and often in artificial additives as well, these are among the most counterproductive choices for anyone trying to reduce inflammation.
Sweetened fruit juices and smoothies. Even 100% fruit juice is low in fiber and high in rapidly absorbed sugars. A large fresh-squeezed orange juice can contain as much sugar as a can of soda.
Specialty coffee and tea drinks. A flavored latte or blended café drink can easily contain 40–60 grams of sugar — more than double the daily limit recommended by the BMJ review.
Flavored yogurts. Often positioned as a health food, but a single serving of flavored yogurt can contain 20–25 grams of added sugar.
Why I'm Even Talking About This
I've spent years working with people in pain. And I'll tell you what I've noticed: the ones who are eating well and keeping sugar low are so much easier to treat. Chronic conditions that should be improving just... linger, in people who aren't making those same choices. I've seen it repeat itself enough times that it's impossible to ignore, and I've felt it in my own body too. And yes, alcohol is on that list too. It's worth knowing that the World Health Organization now states explicitly that no level of alcohol consumption is risk-free — and that alcohol and sugar have more in common metabolically than most people realize.
That said, I want to be clear about something: sugar isn't everything. There are people navigating chronic illness, genetic conditions, old injuries, and deep structural challenges in their bodies that have nothing to do with what they're eating. Diet is one piece of a much more complex picture, and I never want this to read as though food choices are the whole story. They're not.
The truth is, most of us are doing the best we can. And the food system we live inside makes that genuinely hard. Sugar is everywhere, in everything, often hidden behind names we don't recognize on labels we don't have time to read. This isn't about willpower or discipline. It's just information. A little more awareness, here and there, might give us each just a bit more agency. Because let's be clear: our food system was not designed with your health in mind. It was designed around the bottom line, and human health, unfortunately, isn't it.
Most people have some awareness that too much sugar does not leave them feeling their best. They may notice energy crashes, cravings, mood shifts, brain fog, or a general sense of feeling off. But noticing the effect and changing the pattern are two very different things. Sugar does not operate only through choice or willpower. Sweet foods activate the brain’s reward pathways, including dopamine signaling, which helps explain why they can feel comforting, compelling, and difficult to moderate. Over time, repeated exposure to highly sweet, highly processed foods can reinforce cravings and make “just cutting back” much harder than it sounds.
So the struggle is not simply a failure of discipline. There is real biology involved. The knowing-doing gap is real, and it deserves to be understood with honesty and compassion rather than judgment.
And for those who want a reason to believe it's worth trying — the data is encouraging. Among people who reduced sugar and refined carbohydrates, studies have shown that 90% of those with elevated blood sugar experienced measurable improvements, and more than half returned to normal levels entirely. Perhaps more importantly, research tracking behavior change over 18 months found that most healthy dietary shifts don't fade back to baseline — meaning the changes people make tend to actually stick. Research also tells us that people are most likely to change when they genuinely believe it will make a difference — not in the abstract, but for them, in their body, in their life.
The Bigger Picture
Nutrition can attract a certain kind of zealotry: the person at the dinner table who won't stop talking about lectins, the colleague who makes you feel guilty for ordering the pasta. I don't want to be that person, and I don't want this to read that way. Although I'll admit — I have been that person. I have a degree in Nutrition and Dietetics and have spent most of my life trying to sort through what we should and shouldn't eat. I've probably earned the label more than once. I'm hoping to claim the title of "recovering zealot" — though I'll acknowledge that sugar is the one topic I can't seem to stay quiet about. And for what it's worth, I'm usually the first one at the table to say yes to dessert. Because that's exactly when sugar makes sense to me — a real occasion, shared with people you like, something you actually savor. Not the mindless, cumulative kind that sneaks into every ordinary day without you even noticing. When it's intentional and it's joyful and it's finite, it's one of the best things there is. That's not a contradiction. That's the whole point.
Here's a thought I keep coming back to. If enough of us — collectively, imperfectly, in whatever small ways we can manage — start to reduce our demand for products loaded with added sugar and high fructose corn syrup, something larger shifts. Markets respond to demand. The food industry, for all its power, is not immune to what people stop buying. This isn't just personal. The chronic diseases most strongly linked to excess sugar consumption are among the leading drivers of healthcare costs globally. What we eat collectively has consequences that extend well beyond our own bodies — into our healthcare system, our communities, and the health of future generations.
Food is one of life's deep pleasures, and I say that as someone who will absolutely buy a Snickers bar in an airport when stressed enough, who orders cranberry juice on the plane home from a business trip without a second thought, and who has a deep (and probably irrational) weakness for dark chocolate covered almonds, and an arguably deeper one for Häagen-Dazs coffee and vanilla Swiss almond ice cream; both flavors, at the same time, in the same bowl. It's hard to stop with that combination. I won't pretend otherwise.
I'm not entirely sure why I don't eat these things more regularly. I think somewhere along the way, feeling good became more desirable to me than the way sugar tastes in my mouth. But sometimes just a bite really does make all the difference. And I think that's actually the point.
I know that's a lot to put on your next grocery run. And I fully understand that the food system makes it genuinely hard to avoid excessive sugar, it's everywhere, by design. But if any part of this resonates, and if you're someone who can feel the difference after a few days of keeping sugar low and eating food that actually came from the ground and nourishes you, that feeling is worth following. Not because I said so. Because your body already knows, and given the chance, it will show you.
References
Lustig, R. H., Schmidt, L. A., & Brindis, C. D. (2012). Public health: The toxic truth about sugar. Nature, 482(7383), 27–29. https://doi.org/10.1038/482027a
Huang, Y., Chen, Z., Chen, B., et al. (2023). Dietary sugar consumption and health: umbrella review. BMJ, 381, e071609. https://doi.org/10.1136/bmj-2022-071609
Cheng, T. S., et al. (2022). The role of sugar and processed foods in promoting systemic inflammation: a review. Frontiers in Nutrition, 9, 848267. https://doi.org/10.3389/fnut.2022.848267
Calton, E. K., et al. (2022). A systematic review of dietary patterns and inflammation in adults. Nutrients, 14(3), 540. https://doi.org/10.3390/nu14030540
Kopp, W. (2022). High-insulinogenic nutrition — an underestimated risk factor for chronic Western diseases. Nutrients, 14(10), 2091. https://doi.org/10.3390/nu14102091