Here's how a low carb diet can influence inflammation in type 2 diabetes

[Initial note: this article was previously published and updated with scientific and informative criteria. The content is for informational purposes only and does not replace medical advice. Always consult your healthcare professional before changing your therapy or diet.]

IN BRIEF

• Some randomized clinical trials indicate that advice to follow a low carb diet can reduce markers of systemic inflammation in people with type 2 diabetes compared to advice to follow a low-fat diet. [1]
• The reported benefits are often also linked to weight loss and better glycemic control; the direct diet→inflammation relationship remains under evaluation. [2][5]
• Plausible mechanisms include smaller postprandial glycemic excursions, alterations in lipid metabolism, and modulation of the immune system (macrophages, cytokines). [4][6]
• Medium- to long-term evidence is heterogeneous: initial advantages may diminish over time, and diet quality is a determining factor. [5][8]

Abstract: what does science say?

Available research indicates that, in people with type 2 diabetes, a dietary intervention aimed at reducing carbohydrate intake can reduce some markers of inflammation in the short term compared to advice for a low-fat diet. The evidence comes from randomized clinical trials, controlled trials, and systematic reviews that measure biomarkers such as interleukin-6 (IL-6), IL-1 receptor antagonist (IL-1Ra), and C-reactive protein. The results suggest a plausible interaction between glycemic control, weight loss, dietary fat composition, and inflammatory activity; however, many analyses show transient or context-dependent effects, adherence, and diet quality. Therefore, current observations support the plausibility of an anti-inflammatory effect of carbohydrate restriction, but do not allow for a simple and universal causal relationship for all patients.

MAIN SECTION

What do clinical studies show?

In randomized studies conducted on patients with type 2 diabetes, advice to follow a low carb diet has shown significant reductions in some markers of inflammation after 6 months compared to advice to follow a low-fat diet. In particular, a randomized study on patients in primary care reported decreases in IL-6 and IL-1Ra in the low-carb group after 6 months, which were not observed in the low-fat group. [1] Other trials and controlled experiments have documented improvements in glycemia and reductions in triglycerides, effects that can indirectly contribute to reducing the inflammatory state. [2][3] This clinical evidence indicates that, at least in the medium term, changes in macronutrient composition can influence immuno-metabolic parameters, but the extent and persistence of the effects may vary according to protocol, adherence, and therapeutic context. [5]

Plausible biological mechanisms

The biological plausibility linking carbohydrate restriction to a reduction in inflammation includes several overlapping factors. Reducing carbohydrates tends to limit glycemic excursions and postprandial hyperinsulinemia, conditions associated with oxidative stress and activation of inflammatory pathways. [4] Changes in plasma fatty acid composition, ketone body production, and the regulation of macrophages and cytokines (e.g., IL-1, IL-6, TNFα) are other plausible pathways. [6] Preclinical experiments also show that the activation of pancreatic and adipose macrophages can be modulated by the metabolic microenvironment: this links dietary changes, body composition, and local and systemic immune signals. [4]

Dependence on dose, quality, and context

The observed effects depend not only on the absolute reduction in carbohydrates but also on the quality of substitute foods (saturated vs. unsaturated fats, fiber, protein), the duration of the intervention, and adherence. Recent reviews show that benefits on HbA1c and some lipids are more pronounced in the first few months and may decrease over time if adherence is not maintained. [5] Furthermore, a low carb diet with high amounts of saturated fats can have different metabolic consequences than a version with a predominance of unsaturated fats; the "quality" of low carb is therefore crucial to balance glycemic benefits and cardiovascular risks. [6][8]

PRACTICAL SECTION

What it means in practice

For those living with type 2 diabetes, the results suggest that reducing the carbohydrate intake in the diet can be a useful option for lowering some markers of inflammation and improving glycemic control, especially in the first few months. [1][2] However, this is not a universal recommendation: the choice of nutritional strategy must consider the individual clinical situation (medications, comorbidities, nutritional status), the quality of substitute fats and proteins, and long-term sustainability. [5][7] Before adopting a low carb diet, it is advisable to consult a doctor or dietitian to evaluate the adaptation of pharmacological therapy, particularly hypoglycemic agents and insulin, and to define a balanced and monitored Meal plan. [2]

KEY POINTS TO REMEMBER

• A low carb diet can reduce some markers of inflammation in the short to medium term in people with type 2 diabetes. [1]
• Improvements are often accompanied by weight loss and better glycemic control; it is not always possible to separate the direct effect of the diet from the effect of weight loss. [2][5]
• The quality of foods (unsaturated vs. saturated fats, fiber, whole foods) is crucial for overall benefits. [6]
• Long-term effects and cardiovascular implications require further controlled studies. [5][8]
• Any dietary modification must be evaluated in a clinical setting to adapt therapy and monitoring. [2]

Limitations of the evidence

It is important to distinguish between association and causality: many studies report changes in inflammatory biomarkers, but do not always prove that carbohydrate restriction alone is the exclusive cause. Many trials simultaneously show weight loss and pharmacological variations, elements that confound interpretation. [2][5] Furthermore, methodological variability (definition of "low carb," duration, outcome measures, studied population) limits the generalizability of the results. Longer studies, with rigorous controls on macronutrient quality and with clinical endpoints (not just biomarkers) are needed to evaluate safety and benefits in the long term. [5][8]

Editorial conclusion

Clinical literature supports the idea that, for many patients with type 2 diabetes, reducing carbohydrate Intake can help decrease some signs of systemic inflammation and improve glycemic control, at least in the medium term. However, the relationship is neither linear nor universal: the result depends on adherence, weight loss, the quality of substitute nutrients, and pharmacological control. The therapeutic choice must be personalized, based on a risk-benefit assessment conducted by the medical team. Finally, the scientific community requires longer studies with concrete clinical endpoints to establish with greater certainty the extent and duration of these effects.

Editorial note

This article has been updated from a previously published version. The update follows criteria of scientific rigor and informative clarity, with direct reference to clinical studies and systematic reviews. The content is for informational purposes only and does not replace individual medical advice.

SCIENTIFIC RESEARCH

1. Jonasson L, Guldbrand H, Lundberg AK, Nystrom FH. Advice to follow a low‑carbohydrate diet has a favourable impact on low‑grade inflammation in type 2 diabetes compared with advice to follow a low‑fat diet. Ann Med. 2014;46(3):182–187. https://doi.org/10.3109/07853890.2014.894286 [1]
2. Guldbrand H, Dizdar B, Bunjaku B, et al. In type 2 diabetes, randomisation to advice to follow a low‑carbohydrate diet transiently improves glycaemic control compared with advice to follow a low‑fat diet producing a similar weight loss. Diabetologia. 2012;55:2118–2127. https://doi.org/10.1007/s00125-012-2567-4 [2]
3. Davis NJ, Crandall JP, Gajavelli S, et al. Differential effects of low‑carbohydrate and low‑fat diets on inflammation and endothelial function in diabetes. J Diabetes Complications. 2011;25(6):371–376. https://doi.org/10.1016/j.jdiacomp.2011.08.001 [3]
4. Fernemark H, Jaredsson C, Bunjaku B, Rosenqvist U, Nystrom FH, Guldbrand H. A randomized cross‑over trial of the postprandial effects of three different diets in patients with type 2 diabetes. PLoS ONE. 2013;8(11):e79324. https://doi.org/10.1371/journal.pone.0079324 [4]
5. Goldenberg JZ, Day A, Brinkworth GD, et al. Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta‑analysis (BMJ). BMJ. 2021;372:m4743. https://doi.org/10.1136/bmj.m4743 [5]
6. Volek JS, Sharman MJ, Forsythe CE. Limited effect of dietary saturated fat on plasma saturated fat in the context of a low carbohydrate diet. Lipids. 2010;45(11):947–962. https://doi.org/10.1007/s11745-010-3467-3 [6]
7. Saslow LR, Daubenmier J, Moskowitz JT, et al. Twelve‑month outcomes of a randomized trial of a moderate‑carbohydrate versus very low‑carbohydrate diet in overweight adults with type 2 diabetes mellitus or prediabetes. Nutrition & Diabetes. 2017;7:304. https://doi.org/10.1038/s41387-017-0006-9 [7]
8. Foster GD, Wyatt HR, Hill JO, et al. Weight and metabolic outcomes after 2 years on a low‑carbohydrate versus low‑fat diet: a randomized trial. Ann Intern Med. 2010;153(3):147–157. https://doi.org/10.1059/0003-4819-153-3-201008030-00005 [8]