What is the optimal diet?

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Last updated: April 8, 2025View editorial policy

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From the Guidelines

The best diet is one that emphasizes whole, plant-based foods, including plenty of fruits, vegetables, whole grains, and healthy fats, while limiting processed foods, added sugars, and excessive sodium, as recommended by the most recent and highest quality study 1. To achieve this, focus on consuming a variety of whole foods, including:

  • Plenty of fruits and vegetables, aiming for at least five servings a day, as suggested by the American Cancer Society 1
  • Whole grains, such as brown rice, quinoa, and whole-wheat bread, instead of refined or processed grains
  • Lean proteins, like poultry, fish, and legumes, and healthy fats, like nuts, seeds, and avocados
  • Limiting processed and red meats, as well as foods high in added sugars, salt, and unhealthy fats It's also important to stay hydrated by drinking plenty of water throughout the day. Aim for portion control with meals, considering the Mediterranean diet as a model, which has been associated with reduced risk of heart disease and improved longevity 1. Individual factors, such as age, activity level, health conditions, and personal preferences, should influence specific dietary choices, and consulting with a healthcare provider or registered dietitian can help develop a personalized plan. Key dietary recommendations include following traditional dietary patterns, limiting fructose from processed foods and soft drinks, increasing consumption of ω-3 PUFAs and MUFAs, and increasing consumption of high-fiber foods, as outlined in the 2018 study on practical dietary recommendations for the prevention and management of nonalcoholic fatty liver disease in adults 1.

From the Research

Key Components of a Healthy Diet

  • A healthy diet consists of fish, monounsaturated fats from olive oil, fruits, vegetables, whole grains, legumes/nuts, and moderate alcohol consumption, as seen in the Mediterranean diet 2
  • The Mediterranean diet has been shown to reduce the burden of various diseases, including cardiovascular disease, breast cancer, depression, colorectal cancer, diabetes, obesity, asthma, erectile dysfunction, and cognitive decline 2
  • A diet high in plant-based foods, including fresh fruits and vegetables, whole grains, legumes, seeds, and nuts, and low in animal-based foods, particularly fatty and processed meats, is associated with a lower risk of non-communicable diseases (NCDs) 3

Benefits of the Mediterranean Diet

  • The Mediterranean diet has been shown to reduce the risk of type 2 diabetes, with at least five large prospective studies reporting a substantially lower risk of type 2 diabetes in healthy people or at-risk patients with the highest adherence to a Mediterranean diet 4
  • A Mediterranean diet has been associated with improved glycaemic control in subjects with type 2 diabetes, with improvement of HbA1c levels ranging from 0.1% to 0.6% 4
  • The Mediterranean diet may also have cardiovascular benefits, with evidence suggesting that post-infarct or high-risk patients, including diabetic patients, may have cardiovascular benefits from a Mediterranean diet 4

Importance of Fruits and Vegetables

  • Regular consumption of fruits, vegetables, whole grains, and other plant foods has been negatively correlated with the risk of the development of chronic diseases 5
  • A wide variety of fruits, vegetables, whole grains, and other plant foods provide a range of nutrients and different bioactive compounds, including phytochemicals, vitamins, minerals, and fibers 5
  • Potatoes are a low-fat food with unique nutrients and phytochemical profiles, particularly rich in vitamin C, vitamin B-6, potassium, manganese, and dietary fibers 5

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

The Mediterranean diet, its components, and cardiovascular disease.

The American journal of medicine, 2015

Research

Mediterranean diet and type 2 diabetes.

Diabetes/metabolism research and reviews, 2014

Research

Health-promoting components of fruits and vegetables in the diet.

Advances in nutrition (Bethesda, Md.), 2013

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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