The War On Carbs: Are We Fighting The Right Enemy?
Carbohydrates are not the enemy, the packaging is.
A reader responded my article Nine “Hacks” To Lower Your Glucose Spikes with a simple comment:
“Simpler to eat less carbs...”
If carbohydrates raise blood sugar, and damages your health, then eating fewer carbohydrates seems like the logical solution. That reasoning has been reinforced by a decade of social media consensus, bestselling diet books, and a wellness industry that has made carbohydrate fear into a reliable revenue stream.
Americans do over consume carbohydrates, and that contributes to metabolic disease. But the simplistic recommendation “eat less carbs”, although reasonable, fails to account for a more nuanced problem.
What Carbohydrates Actually Do
Your body runs on the two primary fuel sources: carbohydrates and fat.
Fat is energy-dense: breaking down fatty acids via beta-oxidation yields more total ATP per molecule than glucose, but it requires adequate oxygen delivery, functioning mitochondria, and time. Above approximately 60 to 70 percent of maximal aerobic capacity (VO₂max), fat oxidation cannot keep pace with energy demand.
Your muscles need something faster: carbohydrates.
Glycogen, the storage form of glucose packed into liver and skeletal muscle, exists specifically so the body can mobilize fast fuel on demand. It is a biological feature retained across hundreds of millions of years of evolution because rapid fuel mobilization is a survival requirement.
Understanding that carbohydrates are the body’s fast-access fuel reframes the question. The issue is not that carbohydrates exist in your diet, is how much you eat relative to how much you use.
The Activity-Matching Principle
At the peak of his competitive career, Michael Phelps trained five to six hours a day and reportedly consumed somewhere in the range of 8,000 to 12,000 calories, with carbohydrates constituting a substantial fraction of that intake. He was in superior metabolic condition to the vast majority of Americans eating a fraction of that. The reason: he consumed what his body required.
The Acceptable Macronutrient Distribution Range (AMDR) established by the Dietary Guidelines for Americans 2020-2025 and supported by the Institute of Medicine’s Macronutrient Report sets carbohydrate intake at 45 to 65 percent of total daily calories for adults, with a recommended dietary allowance floor of 130 grams per day, the minimum estimated to meet the brain’s glucose requirements without requiring hepatic gluconeogenesis as a primary supply mechanism. Sedentary adults should aim toward the lower end, moderately active adults sits in the middle and heavily active individuals towards the upper end without metabolic consequence, provided the sources are right.
The real problem most Americans have is not that they eat carbohydrates, is that they eat processed carbohydrate products.
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Not All Carbohydrates Are the Same
Even within natural, whole food carbohydrate sources, metabolic response varies. Glycemic index (GI) measures how quickly a carbohydrate-containing food raises blood glucose relative to pure glucose, on a scale of 0 to 100. Useful but incomplete.
Glycemic load (GL) corrects for the portion problem.
Watermelon has a glycemic index of approximately 72, high by standard classification. But a standard serving of watermelon contains relatively little carbohydrate by weight, so its glycemic load is around 4, which is low. Eating watermelon does not produce the same metabolic event as eating an equivalent glycemic-index-matched serving of white sandwich bread.
The Linus Pauling Institute Micronutrient Information Center at Oregon State University has compiled extensive GI and GL tables showing this pattern across dozens of foods that anti-carb messaging routinely condemns (i.e., bananas, pineapple, parsnips) whose glycemic loads at realistic portion sizes are moderate.
GL is the more clinically meaningful number when you are trying to evaluate the actual impact of a food; GI alone generates unnecessary fear. But even GL does not capture the full picture, because it does not account for what food scientists call the food matrix.
The Food Matrix And Industrial Processing
The food matrix is the physical cellular architecture of whole food. That structure governs how quickly carbohydrates are absorbed, independently of their chemical composition.
A whole banana delivers glucose within an intact cellular matrix. The carbohydrates are physically encased in plant cells that must be mechanically disrupted by chewing and then enzymatically broken down by digestion before absorption begins.
The result: glucose enters the bloodstream gradually.
Commercial banana pudding made with modified corn starch, sucrose or high-fructose corn syrup, refined wafers, emulsifiers, and artificial banana flavoring has no meaningful matrix. The industrial manufacturing process has destroyed whatever structure existed in the source ingredients and replaced it with rapidly-absorbed refined starches and free sugars. The glucose arrives faster, the insulin demand is higher, and the satiety signal is weaker: the food matrix was profoundly altered before it reaches your mouth.
A systematic review by Dahl et al. published in Frontiers in Nutrition (2021, DOI: 10.3389/fnut.2021.673364) found that intact starch structure significantly reduces postprandial glucose and insulin response compared to processed forms with identical macronutrient content. Earlier foundational work by Haber et al. published in the Lancet (1977) demonstrated that equal carbohydrate loads from intact apple, pureed apple, and apple juice produced different insulin responses. Juice and puree apple increased insulin demand despite producing similar glucose curves suggesting that matrix disruption elevates insulin response even when the glucose profile looks comparable. A 2025 overview in Critical Reviews in Food Science and Nutrition (Forde et al., DOI: 10.1080/10408398.2025.2453074) synthesized the current state of food matrix science and confirmed that physical food structure is an independent determinant of metabolic response.
Sourdough bread made through long fermentation produces meaningfully lower glycemic response than the same flour baked into conventionally produced commercial bread. The fermentation process partially pre-digests the starch, modifies the gluten matrix, and lowers the pH, all of which slow glucose absorption.
Same flour, different process, different metabolic results.
Legume-based pasta made from lentil, chickpea, or black bean flour, provides carbohydrate alongside fiber and protein in a matrix structure that further attenuates postprandial glucose response, making it a practical and under appreciated option for readers managing blood sugar.
So How About Ketogenic Diets
The ketogenic diet is the ultimate expression of the low carb philosophy.
In type 2 diabetes management, short-term ketogenic interventions have produced clinically meaningful reductions in HbA1c and triglycerides and achieved diabetes remission in some patients. In refractory epilepsy, ketogenic diet is an established therapeutic tool with decades of clinical use.
The honest limitation is that most ketogenic diet research is short-term. Patikorn et al. published an umbrella review of meta-analyses of randomized clinical trials (RTC) in BMC Medicine (2023, DOI: 10.1186/s12916-023-02874-y) covering 68 RCTs. The median trial follow-up was 13 weeks. Of 115 associations examined, only four were supported by high-quality evidence: reduced triglycerides in two analyses and reduced seizure frequency. Thirteen weeks is not long enough to evaluate a dietary pattern most of its proponents recommend for life.
Meta-analyses of ketogenic diet RCTs consistently show favorable effects on triglycerides and HDL, but also a mean LDL-C increase of approximately 8.5 mg/dL (Mozafari et al., ScienceDirect 2026, DOI: 10.1016/j.jacl.2026.00261; American Journal of Clinical Nutrition meta-analysis, 2024, DOI: 10.1016/j.ajcnut.2024.00445). Early blood pressure reductions seen at six months were not sustained at twelve months and beyond. At least one analysis suggested the LDL increase may reflect larger, less atherogenic particle fractions but that question remains unresolved.
The evidence-based clinical position on ketogenic diets is this: validated short-term therapeutic tool for specific populations, unanswered question as a long-term dietary pattern for general use.
The Real War
Here is what the evidence consistently points toward: ultra-processed food, not carbohydrates, is the primary dietary driver of the metabolic disease epidemic.
The most compelling evidence comes from a randomized controlled trial by Hall et al. published in Cell Metabolism (2019, DOI: 10.1016/j.cmet.2019.05.008). He recruited 20 adults and admitted them to an inpatient metabolic research ward for four weeks. Participants were randomly assigned to either an ultra-processed diet or an unprocessed diet for two weeks, then crossed over to the other condition. Both diets were matched for presented calories, macronutrients, sugar, sodium, and fiber. Participants were offered as much food as they wanted and told to eat as much or as little as they liked.
On the ultra-processed diet, participants consumed an average of 508 additional calories per day, weight gain followed. On the unprocessed diet, they spontaneously ate less and lost weight. The macronutrient composition on paper was identical, the difference was the food matrix.
This is causal evidence is limited by a sample of 20 participants in a controlled inpatient setting, and a short 28-day duration. But the direction of causality is established: ultra-processed food drives overconsumption through mechanisms that operate independently of macronutrient content.
Those mechanisms are not fully characterized. Current hypotheses include disrupted satiety signaling, altered oral processing (ultra-processed food requires less chewing, which affects cephalic phase insulin and satiety hormones), direct effects of food additives on gut microbiome and appetite regulation, and hyperpalatable combinations of fat, sugar, and salt engineered to override normal satiation. None of these mechanisms have carbohydrates as the primary variable.
The food industry has benefited from a public discourse fixated on macronutrients. Macronutrient anxiety is commercially useful: it sells low-carb products, ketogenic supplements, protein bars, and meal replacement systems.
It also redirects attention away from the manufacturing process: the destruction of the food matrix, the addition of refined starches and free sugars, the replacement of real ingredients with engineered substitutes.
That is the actual problem.
The myopic public focus about carbohydrate grams protects industrial food from scrutiny.
Where This Leaves You
You need to recognize the difference between a food with an intact matrix and a product whose matrix has been industrially destroyed. An apple or a banana are not metabolic threats after all. Match your carbohydrate intake to your activity level, choose whole food sources with intact matrices, reduce ultra-processed food.
The real problem is the processing, not the macronutrients.
The war on carbohydrates was never the right war. It was a war fought on the wrong battlefield, against the wrong enemy, while the actual problem continued largely undisturbed. The reader who wrote “simpler to eat less carbs” was not wrong. But simpler is only useful if it aims at the right target.
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