When it comes to diabetes management, some academic papers remain cautious, waiting for “more evidence” before recommending specific dietary interventions. For example, a recent review on glycemic variability (GV) suggested that while fluctuations in blood sugar may contribute to complications, the exact role of GV is still unclear, and therefore more long-term studies are needed. This is a fair scientific position — but it risks missing an important point: we already have robust, real-world evidence showing that targeted dietary changes can improve blood sugar control now.
Rather than focusing solely on how to measure GV, we should act on what is proven to work — choosing low glycaemic index (GI) foods and following a low-carbohydrate, high-fat (LCHF) dietary pattern.
The Problem with Focusing on GV Alone
GV is an interesting metric. It captures how much blood sugar swings up and down throughout the day. The review in question highlights that GV might be linked to complications such as retinopathy, nephropathy, and cardiovascular events. However, it ultimately admits that the evidence is inconclusive, and no definitive target for GV control has been established.
The danger here is paralysis by analysis: waiting for perfect proof before making practical recommendations. Meanwhile, millions continue to suffer from uncontrolled diabetes — a condition that we already know can be improved through better food choices.
The Proven Power of Low-GI Foods
Low-GI foods digest more slowly and release glucose gradually into the bloodstream, avoiding the sharp spikes that stress the pancreas and cause large GV swings. Meta-analyses of randomized controlled trials (RCTs) have shown that low-GI diets can reduce HbA1c — the long-term marker of blood glucose — by around 0.31% compared to high-GI diets1. That may sound small, but it’s a clinically meaningful improvement, on par with the effects of some medications, and it comes without side effects.
Why Low-Carb, High-Fat Diets Work Even Better
While low-GI diets improve carbohydrate quality, low-carb diets address carbohydrate quantity. In a large dose-response meta-analysis of 50 RCTs, every 10% reduction in carbohydrate intake (as a percentage of total calories) led to an average 0.20% drop in HbA1c at six months, with additional benefits for fasting glucose, body weight, and triglycerides2. This effect was consistent and showed a clear “more carb reduction, more benefit” pattern.
In practical terms, LCHF diets achieve this by replacing carbs with healthy fats and adequate protein, shifting the body toward burning fat for energy and reducing the need for insulin. The result is not just lower blood sugar, but often reduced medication dependence — and in some cases, remission of type 2 diabetes.
Evidence of Remission
One systematic review found that at six months, 57% of people on low-carb diets achieved diabetes remission (defined as HbA1c below 6.5% without medication) compared to just 31% on control diets3. That’s not a small win — that’s life-changing. Although the benefit tends to diminish by 12 months in some studies, this is often due to people drifting away from the diet rather than the diet itself losing effectiveness.
Addressing the Critics
Some will point out that not all studies show a lasting advantage for low-carb diets, especially over two or more years. That’s true — but the same is also true for almost every dietary intervention ever tested. The key to long-term success is adherence and proper formulation. A poorly planned LCHF diet high in processed meats and low in micronutrients is very different from a well-formulated version rich in vegetables, quality proteins, and healthy fats.
Others raise concerns about LDL cholesterol increases on very-low-carb or ketogenic diets. This is a legitimate point, and anyone adopting such a diet should monitor their lipid profile and focus on healthy fat sources like olive oil, nuts, seeds, and fatty fish.
The Bottom Line
The science is already clear enough for action: both low-GI and low-carb diets can meaningfully improve blood sugar control, reduce glycaemic variability, and in many cases, allow people with type 2 diabetes to reduce or even stop medications. These are not fringe ideas — they are supported by dozens of RCTs, meta-analyses, and real-world studies.
So while researchers continue to debate the finer points of GV measurement, the practical message for patients and clinicians is simple:
Swap high-GI carbs for lower-GI alternatives, cut back on total carbs, and replace them with healthy fats and protein. Your blood sugar — and your long-term health — will thank you.
Footnotes / References
- Reynolds A, et al. “Effect of low glycaemic index or glycaemic load dietary patterns on glycaemic control and cardiometabolic risk factors in diabetes: Systematic review and meta-analysis of randomised controlled trials.” BMJ 2019; 366:l5003. ↩
- Chiavaroli L, et al. “Effect of carbohydrate restriction on glycemic control in adults with diabetes: A systematic review and dose-response meta-analysis of randomized controlled trials.” Am J Clin Nutr 2022; 115(6): 1460–1472. ↩
- Goldenberg JZ, et al. “Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: Systematic review and meta-analysis of published and unpublished randomized trial data.” BMJ 2021; 372:m4743. ↩
