Scientific Research

25 adults with type 2 diabetes ate a low-fat vegan diet for 16 weeks without counting calories: weight, liver fat and HbA1c fell, and some reduced their metformin dose. What this study without a control group shows, what it cannot, and who funded it.

A new Tel Aviv study of 54 vegan and 176 non-vegan pregnant women found lower protein intake in vegans, and linked the share of protein and its leucine content to birth weight. What it shows, its limits and the nutrients that matter most in pregnancy.

In the US NHANES survey, 68% of adults who called themselves vegetarian reported meat, poultry or fish in their 24-hour dietary recalls. How vegetarians are defined can change what the same data show.

A German study found lower height and BMI scores in vegan children aged 10 and over than in vegetarians. The vegan group was 12 participants; what the study can and cannot show, and what ESPGHAN advises parents.

In two cohorts of over-65s in China and the US, people classed as vegetarian had higher mortality. How vegetarian was defined, reverse causation, earlier studies of the same cohort, results elsewhere and practical points for older vegans.

In the US REGARDS cohort of 14,776 adults, a healthy plant-based diet was linked to 28% lower coronary artery disease risk, while the overall plant score gave mixed results. How it compares with the 29 September meta-analysis, and why diet scores need care.

On World Heart Day, a new meta-analysis of 19 prospective studies: plant-based eating lowers cardiovascular risk, but only when the plants are whole grains, legumes, nuts and vegetables. A plant-based diet built on sugary drinks, refined grains and sweets raised the risk.

Public health gives two pieces of advice side by side: eat more plant foods, eat fewer ultra-processed foods. For a young vegan they collide, because fortified plant milks are classified as ultra-processed. A Swedish study of 235 young people measured the collision: among vegans, a median of 98 per cent of vitamin B12 and 91 per cent of vitamin D came from ultra-processed food. Yet those vegans ate the most fibre, the most unsaturated fat and the least saturated fat, with no difference in sugar, salt, calories or BMI. And when the researchers classified the same foods a second way, the difference between the diet groups disappeared altogether.

People eat a fairly constant weight of food each day, so the calories packed into each gram decide the total. In a 16-week randomised trial, moving to a low-fat vegan diet cut dietary energy density from 1.1 to 0.7 kcal/g while the weight of food eaten stayed the same, and daily intake fell 357 kcal below the control group with no calorie limit set. The paper also shows where each food group sits, and why lower is not a goal for everyone.

A new risk assessment pooled mycotoxin measurements from 413 plant-based meat alternatives and drinks in Italy and the UK, then modelled 25%, 50% and 100% replacement of meat and milk. Four toxin groups drove every threshold exceedance, children came out highest, and the studies that measure people rather than model them disagree with each other.