We often hear “Go plant-based!” as the mantra for a healthy life. But the Nature Medicine study adds a new layer:
What if your diet could be good for both your health and the planet?

This post explores two closely related, yet distinct, eating patterns:

• 🌱 hPDI – the Healthful Plant-Based Diet Index

• 🌍 PHDI – the Planetary Health Diet Index

Both focus on plants, but with different priorities. One focuses purely on health. The other aims to balance human and environmental well-being.

So, how do they compare when it comes to healthy aging?

🌱 Healthful Plant-Based Diet Index (hPDI)

The hPDI gives positive scores to healthy plant foods like:

• Whole grains

• Fruits

• Vegetables

• Legumes

• Nuts

• Plant oils

It penalizes:

• Animal foods (even fish, dairy, and eggs)

• Less healthy plant foods (like refined grains, sugar-sweetened beverages, fried snacks)

🧪 In the Study:

• hPDI had the weakest association with healthy aging among the eight diets

• Still helpful, but less powerful than mixed diets that included some healthy animal-based foods

🤔 Why?

Completely eliminating all animal foods may lead to:

• Lower intake of vitamin B12, iron, zinc, omega-3, and high-quality protein

• Nutritional gaps if not carefully planned

This matters even more as we age, when muscle preservation, cognition, and immunity depend on adequate nutrient intake.

🌍 Planetary Health Diet Index (PHDI)

Designed by the EAT-Lancet Commission, the PHDI promotes a diet that:

• Supports human health

• Minimizes environmental impact

It emphasizes:

• Mostly plants, but allows modest amounts of animal foods

• Focus on low greenhouse gas emissions

• Minimizes red meat, ultra-processed foods, and added sugars

🧪 In the Study:

• PHDI had one of the strongest associations with healthy aging

• Especially helpful for:

  • Cognitive health

  • Living to age 70 and beyond

🌾 In Indian Kitchens:

The PHDI aligns well with traditional semi-vegetarian Indian diets:

• A plate of rice + sambar (dal + vegetables)

• A spoon of ghee or sesame oil

• Some curd

• Weekly fish or egg dishes

• Seasonal fruits and greens

This balance seems to support both personal and planetary longevity.

🍽 Comparing the Two:

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⚖️ The Balanced Message

Going plant-based doesn’t have to mean going extreme.
You can love the planet, love your body, and still include:

• Curd or buttermilk

• Eggs twice a week

• Fish or chicken occasionally

What matters more is minimizing processed junk, and maximizing natural, whole foods.

🪔 Final Thought

Our ancestors understood balance. A village meal of rice, greens, dal, and curd—cooked fresh, shared with family—was inherently sustainable and health-supportive.

Today’s science is simply catching up.

So if you’re looking to eat right for your own aging and for future generations, the planetary health approach may be your best bet.