Beyond UPFs: Why Refined Carbohydrates and Sugars Are the Bigger Metabolic Threat

Ultra-processed foods (UPFs) have emerged as a major villain in public health debates. Defined by their industrial formulations, additives, and packaging, UPFs are consistently linked with obesity, diabetes, and heart disease. Reducing UPF consumption is an important step for population health.

But here’s the catch: not all metabolic harm comes neatly packaged in a box or bag. Even if we eliminate the worst UPFs, the broader issue of refined carbohydrates and excess sugars may remain largely unaddressed. For those already struggling with metabolic dysfunction, the problem isn’t only processing—it’s also how strongly a food raises insulin and blood sugar. And unfortunately, even unprocessed carbs can adversely impact blood sugar for those who are susceptible. 

The Metabolic Toll of Refined Carbs and Sugars

When we eat refined carbs—white bread, pasta, sugary cereals, pastries, sweetened beverages—they are rapidly broken down into glucose. This leads to a sharp rise in blood sugar, triggering a surge of insulin. For people who are metabolically healthy, occasional spikes may be tolerated. But for those with insulin resistance, prediabetes, or type 2 diabetes, these surges worsen the underlying problem.

Chronically elevated insulin leads to:

• Fat storage and weight gain, often in the form of the most concerning fat – visceral fat.
  
• Higher triglycerides and lower HDL cholesterol, both markers of increased cardiac risk.
  
• Increased blood pressure through sodium retention, a key driver of heart and vascular disease.
  
• Greater hunger and cravings, as rapid spikes and crashes destabilize appetite, leading to overeating and weight gain.
  

Over time, this vicious cycle drives metabolic syndrome and related chronic diseases.

Why UPF Focus Alone Falls Short

It’s tempting to think of UPFs as the root cause of all metabolic dysfunction. After all, they dominate modern diets and are strongly associated with poor health outcomes. But UPFs are not a single nutrient category—they’re a catch-all term for foods made with additives, stabilizers, artificial flavors, and refined ingredients.

While cutting UPFs will likely improve overall health, it doesn’t automatically address the refined carbohydrate load. Consider these scenarios:

• A plate of white rice, white bread, and fruit juice at home isn’t technically “ultra-processed.” But metabolically, it floods the body with glucose just as surely as soda or candy.
  
• A “natural” smoothie with fruit juice, bananas, and honey might seem healthy, but can contain 50+ grams of sugar—enough to raise blood sugar significantly.
  
• Even some “whole grain” products, marketed as health foods, can raise glucose and insulin substantially because of their processing and portion sizes.
  

In other words, a narrow focus on UPFs risks leaves out other drivers of metabolic dysfunction, such as excess carbs and sugars.

The Role of Metabolic Health

The impact of excess or refined carbs isn’t uniform—it depends on one’s metabolic state. Someone who is insulin sensitive, active, and lean may tolerate higher carb intake without issue. But for the growing majority of adults who are insulin resistant—estimates suggest more than 1 in 3 U.S. adults—those same foods can accelerate metabolic decline.

This is why blanket dietary guidelines that emphasize “whole grains” and “limit fat” miss the mark. For individuals already struggling with obesity, prediabetes, or type 2 diabetes, refined carbs and even excessive “healthy carbs” can perpetuate disease.

Why Cravings Make It Worse

Refined carbs and sugars also hijack appetite regulation. Unlike protein or fiber-rich foods, they do little to promote satiety. Instead, they trigger dopamine pathways similar to addictive substances, leading to overconsumption.

This helps explain why simply advising people to “eat less” is ineffective. When the diet is built on refined carbs, hunger and cravings make sustained calorie restriction nearly impossible. Addressing carbohydrate quality and quantity is essential.

A Better Path Forward

To meaningfully improve metabolic health, we need to go beyond UPFs and also address refined carbs and sugars head-on. That means:

1. Refocusing guidelines on metabolic outcomes. Instead of prescribing fixed diets, evaluate eating patterns based on whether they improve insulin sensitivity, blood sugar, triglycerides, and HDL cholesterol.
   
2. Prioritizing protein and healthy fats. These foods promote satiety, preserve lean mass, and stabilize blood sugar, reducing reliance on refined carbs for energy.
   
3. Educating about “hidden sugars.” Fruit juices, smoothies, flavored yogurts, and energy bars can contain sugar loads rivaling soda. Transparency and labeling reforms will help identify these problematic products.
   
4. Tailoring advice to metabolic state. Those with insulin resistance should adopt lower-carb approaches to reverse metabolic dysfunction.
   
5. Improving the food environment. Whole, nutrient-dense foods must be more accessible and affordable than refined-carb staples and sugar-laden products.
   

The Bottom Line

Targeting ultra-processed foods is a useful public health strategy, and it’s a good start. But it’s not enough. Refined carbohydrates and sugars—whether in UPFs or disguised as “healthy” foods—are central drivers of metabolic disease.

For metabolically unhealthy individuals, simply swapping one processed product for a “natural” carb-heavy alternative won’t solve the problem. We must confront the underlying issue: diets overloaded with glucose-raising foods in a population already burdened by insulin resistance.

A true solution requires reframing our nutrition policies around metabolic health outcomes—not just food categories. Because in the end, it’s not whether a food is “processed” or “natural” that matters most—it’s what it does to our metabolism.