For years, debates about plant‑based diets in pregnancy and infancy have been shaped more by opinion than evidence. Concerns about nutrient adequacy, growth faltering, and long‑term development often dominate public conversation, even as plant‑forward eating becomes more common in many parts of the world.

Now, one of the largest studies ever conducted on infant growth and family dietary patterns offers a clearer, more nuanced picture — and it’s far more reassuring than many might expect.

Published in JAMA Network Open earlier this month, a nationwide Israeli cohort study followed more than 1.19 million infants from birth to age two, comparing growth trajectories across vegan, vegetarian, and omnivorous households. The scale alone makes it a landmark piece of research, but its findings are what truly shift the conversation.

Real-world growth

The study examined infants born between 2014 and 2023, drawing on millions of measurements of weight, length, and head circumference. Families were classified as vegan, vegetarian, or omnivorous based on their household diet once complementary feeding began.

The central question: Do infants raised in plant‑based households grow differently from those in omnivorous homes?

The answer: Not in any clinically meaningful way.

Across the first two years of life, growth patterns were remarkably similar. Differences in average weight, length, and head circumference were tiny — typically corresponding to less than 0.2 of a WHO z‑score, far below thresholds considered clinically significant. By age 24 months, the growth curves of vegan, vegetarian, and omnivorous infants were nearly indistinguishable.

Early differences

The study did identify some modest differences in early infancy:

• Infants in vegan households were, on average, slightly lighter and shorter at birth — about 100 g lighter and less than 0.5 cm shorter than omnivorous infants.
• Underweight was more common in early infancy among vegan infants (7.2%) compared with omnivorous infants (4.7%).
• Stunting rates were similar across all groups at around 7%.

These early differences, however, diminished rapidly. By 24 months:

• Stunting prevalence fell to 3.9% in vegan infants, 3.4% in vegetarian infants, and 3.1% in omnivorous infants — not statistically different.
• Underweight and overweight rates were low and similar across all groups.
• Adjusted models showed no meaningful differences in growth outcomes once birth weight and other factors were accounted for.

In other words, while vegan infants may start slightly smaller, they catch up.

Early differences

But why might vegan infants start out smaller? The researchers note several possible explanations:

• Vegan mothers in the study tended to have lower parity, higher socioeconomic status, and longer breastfeeding duration — all factors that can influence birth weight.
• Previous research suggests vegan mothers may have lower pre‑pregnancy BMI, which is associated with slightly smaller infants.
• Nutrient intake during pregnancy — particularly protein, vitamin B12, iodine, iron, and omega‑3 fatty acids — may differ in vegan diets if not carefully planned.

However, because the study did not include detailed maternal dietary data, these remain hypotheses rather than confirmed causes.

Breastfeeding patterns

One of the most striking findings was that vegan and vegetarian mothers breastfed longer — both exclusively and partially — than omnivorous mothers. For example:

• 65.3% of vegan mothers exclusively breastfed for 1–6 months, compared with 50.1% of omnivorous mothers.
• Nearly half of vegan mothers continued partial breastfeeding for 12 months or more.

Longer breastfeeding is associated with numerous benefits, including reduced infectious disease risk, improved cardiometabolic outcomes, and lower obesity rates later in childhood. The study found that while prolonged breastfeeding was associated with a slightly higher odds of stunting, it was also linked to lower overweight risk at age two — a trade‑off that aligns with global research.

Key takeaway

The key takeaway is clear: well‑planned vegan and vegetarian diets can support healthy infant growth. The study reinforces what many paediatric nutrition experts already advise:

• Plant‑based diets are safe for infants when thoughtfully designed.
• Supplementation — especially vitamin B12, and in some cases vitamin D, iodine, iron, calcium, and omega‑3s — is essential.
• Regular growth monitoring remains important for all infants, regardless of diet.

The findings also challenge the assumption that plant‑based diets inherently compromise growth. Instead, they highlight the importance of diet quality, prenatal nutrition, and ongoing support from health professionals.

The food landscape

As more families adopt plant‑forward eating for health, environmental, or ethical reasons, high‑quality evidence like this becomes crucial. This study — with its enormous sample size and detailed longitudinal tracking — provides some of the strongest reassurances to date that infants in vegan and vegetarian households can grow just as well as their omnivorous peers.

It also underscores a broader truth: nutrition in the first 1,000 days is about patterns, not labels. Whether a family eats plant‑based or omnivorous, the essentials remain the same:

• Adequate energy intake
• Sufficient protein
• Key micronutrients
• Responsive feeding
• Regular monitoring
• Access to supportive healthcare

When these foundations are in place, children thrive.