Most PWS patients meet nutrient targets but struggle with calorie control
Researchers advocate for individualized diet plans to balance energy, nutrition
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Adolescents and adults with Prader-Willi syndrome (PWS) in Australia are largely following national healthy eating guidelines, yet they still face high rates of obesity due to consuming significantly more than what’s recommended for the condition.
According to a new study, while these patients are choosing the right types of food, their calorie needs are much lower than those of the general public, and standard dietary advice is not enough to prevent weight gain.
The research highlights a significant “energy gap,” showing that mean energy intake exceeded PWS-specific recommendations by more than 80% in both adolescents and adults. The study suggests that for people with PWS, weight management requires a specialized, highly restrictive approach that goes beyond general nutrition advice to focus on extreme calorie control.
“Overweight and obesity occurred despite strong adherence to Australian healthy dietary guidelines,” researchers wrote. “PWS appropriate energy-restricted diets, including low-fat, calcium and iron-rich foods, are recommended to enhance health outcomes.”
The study, “Assessment of Nutrition Quality in People With Prader–Willi Syndrome in Australia,” was published in the Journal of Human Nutrition and Dietetics and conducted by a team of researchers in Australia.
Navigating the energy requirements of PWS
PWS is a complex genetic disorder characterized by a wide range of symptoms, including hyperphagia (insatiable hunger) and a slower metabolism. Because of these factors, the daily recommended energy intake for those with PWS is 60% to 80% of what is recommended for the general public.
To assess how well patients are meeting these strict guidelines, researchers analyzed the diets of 18 adolescents and 26 adults. The study was a secondary analysis of initial data from participants in an Australia-based Phase 2 clinical trial (ACTRN12620000416998) that assessed the effect of exercise on muscle strength in people with PWS.
“The prevalence of overweight and obesity in adolescents with PWS is estimated to be around 40% and increases to 82%–98% in adulthood,” the researchers wrote.
In the study, 58% of adolescents and 81% of adults were overweight or obese. The data showed that those who struggled most with their weight were also the least likely to follow the specific PWS calorie restrictions.
Adolescents had a mean age of 15.5 years and were mainly boys (55.6%), while adults had a mean age of 27.1 years and were mainly women (53.8%).
“The proportion of participants who were above the healthy weight range did not differ by age group or living arrangements [whether they lived with their family],” the team wrote.
While most participants were successful in hitting the “macronutrient” targets — balancing protein, carbohydrates, and fiber — the volume of energy consumed remained the primary hurdle. This was compounded by a high intake of sodium and saturated fats, which exceeded recommended levels in the majority of patients.
The study revealed that while patients ate lean meats, fruits, and vegetables, they often fell short in other “core” food groups, failing to meet the daily requirements for calcium, iron, and magnesium. These nutrients are critical for bone health and muscle function. Specifically, intake of grains and dairy was below recommended levels, leading to deficiencies in several vital minerals.
Dietary intake data were collected at the start of the trial through a parent or caregiver using the Australian Eating Survey, a web‐based food frequency questionnaire to assess dietary intake over the past three to six months.
Interestingly, participants living in supervised residences showed higher vegetable intake but a lower variety of fruit.
Results showed that, overall, the mean energy intake exceeded recommendations for PWS by 84% in adolescents and 88% in adults, with 15 adolescents (88%) and 21 adults (81%) exceeding the recommendations.
The PWS-recommended macronutrient intake includes 25% protein, 45% carbs, 30% total fat, and at least 20 g of fiber per day. Most participants were within these recommendations for protein (61% of adolescents and 58% of adults), carbs (56% and 54%), fat (61% and 77%), and fiber (95% and 81%).
However, saturated fat intake exceeded recommended levels in 83% of adolescents and 65% of adults. About 28% of adolescents and 19% of adults met all macronutrient recommendations. Participants who were overweight or obese consumed significantly more grams of saturated fat than those with a healthy or low weight.
Need for individualized dietary support
Although their discretionary food intake was lower than that of the general population, more than half exceeded the recommended limits for these foods, which include pizza, hamburgers, sweetened beverages, sweet foods, and snacks.
The researchers concluded that meeting general dietary guidelines is simply “insufficient” for effective weight management in PWS.
“Our results add evidence to the importance of continuous, individualised dietary interventions that address both energy control and nutritional adequacy,” they wrote.
