Dietary Patterns in Cardiovascular and Diabetes Care: What the Research Supports

Why Dietary Patterns — Not Individual Foods — Are What Research Examines

Nutrition research has increasingly shifted away from studying isolated nutrients toward examining overall dietary patterns. This reflects how people actually eat: foods consumed together influence metabolism in ways no single item can replicate. For conditions like cardiovascular disease and type 2 diabetes — which share overlapping risk factors including insulin resistance and systemic inflammation — the pattern-level approach is especially relevant. Understanding how diabetes and heart disease are biologically connected helps explain why diet recommendations for one condition so often align with the other.

Three dietary patterns dominate the peer-reviewed literature on cardiometabolic health: the Mediterranean diet, the DASH (Dietary Approaches to Stop Hypertension) diet, and various low-carbohydrate frameworks. Each has a distinct evidence base, practical profile, and set of trade-offs worth examining.

Comparing the Three Most-Studied Dietary Approaches

The table below summarises how these patterns compare across the dimensions most relevant to heart and diabetes care.

Despite their differences, all three patterns converge on reducing ultra-processed foods, added sugars, and refined grains — a common thread that researchers consider meaningful independent of any specific framework.

What the Evidence Shows for Each Pattern

Mediterranean Diet

Characterised by high intake of vegetables, legumes, whole grains, fish, and olive oil — with moderate wine consumption in some study designs — the Mediterranean pattern has been evaluated in large randomised controlled trials. The PREDIMED trial, published in the New England Journal of Medicine, found it associated with reduced major cardiovascular events compared to a low-fat control diet in adults at high cardiovascular risk. Evidence also supports modest improvements in fasting glucose and insulin sensitivity. Its relatively high fat content (predominantly unsaturated) distinguishes it from older low-fat dietary guidance.

DASH Diet

Originally designed to address hypertension, the DASH diet emphasises fruits, vegetables, low-fat dairy, and limits on sodium and saturated fat. Clinical trials have demonstrated consistent reductions in blood pressure — a major cardiovascular risk factor — and some benefit for LDL cholesterol. Its effects on blood glucose are less pronounced than low-carbohydrate approaches, though it remains widely recommended by cardiovascular professional bodies. It is often easier to sustain long-term given its flexibility.

Low-Carbohydrate Dietary Patterns

These approaches — ranging from moderate carbohydrate reduction to ketogenic frameworks — have shown notable short-term reductions in HbA1c (a measure of average blood sugar) and triglycerides, with improvements in HDL cholesterol in some studies. However, effects on LDL cholesterol are variable, and long-term cardiovascular outcome data are more limited. The 2019 consensus report from the American Diabetes Association acknowledged low-carbohydrate eating as a viable short-term option for glycaemic management, while noting that individual responses differ significantly.

Putting the Evidence Into Practice

For individuals managing either or both conditions, the research does not point to one obligatory eating pattern. Rather, it supports the idea that a diet built predominantly from whole, minimally processed foods — regardless of exact macronutrient ratios — is associated with better cardiometabolic outcomes than the typical Western diet high in ultra-processed foods.

Practical daily management involves more than diet alone. See our guide to living with both diabetes and heart disease for broader lifestyle and monitoring strategies. Staying current with relevant screenings is also important — our annual health screening checklist outlines what to discuss with your care team.

It is also worth noting that some common beliefs about diet and heart disease have been shown to be misleading; our piece on heart disease myths addresses several of these directly.

This article is for informational and educational purposes only and does not constitute medical advice. Anyone managing cardiovascular disease, diabetes, or related conditions should consult a qualified healthcare professional before making changes to their diet or treatment plan.