Key takeaways:
- Men with prostate cancer and overweight or obesity on androgen deprivation therapy lost significant weight with a whole-food plant-based diet.
- The intervention improved BMI and total mass, too.
CHICAGO — A whole-food plant-based diet can significantly increase weight loss for men with prostate cancer and overweight or obesity who are receiving androgen deprivation therapy.
Data from a randomized trial, presented at ASCO Annual Meeting, showed men who received the dietary intervention and coaching lost approximately 8 pounds more over 6 months than those who received counseling alone. They also had significant improvements in BMI, total mass and fat mass.
A whole-food plant-based diet can significantly increase weight loss for men with prostate cancer and overweight or obesity who are receiving androgen deprivation therapy. Image: Adobe Stock.
David M. Nanus
“It’s hard to lose weight. For this patient population on therapy, it’s very hard to lose weight,” David M. Nanus, MD, interim chief of the division of hematology and medical oncology at Weill Cornell Medicine, told Healio.
“When asked by overweight men on treatment what can I do as a patient, I tell them, diet and exercise can make a difference, and a whole-food plant-based diet is probably the best diet you can do for yourself.”
‘Strong relationship’
Prior research has shown that obesity has an association with prostate cancer progression, according to study background.
“There’s a long and strong relationship between obesity and prostate cancer,” Nanus said. “When diagnosed with prostate cancer, overweight and obese men will do worse.”
Androgen deprivation therapy is an effective treatment for prostate cancer, but it also can lead to weight gain and insulin resistance, in addition to increasing risk for cardiovascular disease and diabetes.
“Patients gain weight on hormonal therapy,” Nanus said. “We frequently will refer overweight patients to a nutritionist. More often than not, when they return 3 months later, very little weight has been lost.”
Previous studies have demonstrated a whole-food plant-based diet can help with weight loss, lower inflammation and promote insulin sensitivity.
Healio also previously reported plant-based diets significantly improved sexual function, vitality, urinary obstruction and incontinence among men with prostate cancer.
Nanus and colleagues investigated whether a whole-food plant-based diet could improve weight loss for these patients.
“With a vegetarian diet, you could have some Pringles. That’s vegetarian. You could eat a lot of processed food. There are a lot of processed grains out there that aren’t that healthy,” Nanus said. “Whole food is really what it sounds like. It’s natural grains, fruits, vegetables. No fish, no eggs, no dairy, no meat. It’s a lot of beans, a lot of cruciferous vegetables.”
Researchers randomly assigned 60 men (median age, 73 years; 65% white) with prostate cancer who were receiving androgen deprivation therapy and had a BMI of at least 27 kg/m2 to a whole-food plant-based diet (n = 29) or control (n = 31).
The intervention included 12 prepared and delivered meals for weeks 1 through 4, six meals for weeks 5 through 8, and coaching to self-prepare meals from weeks 9 through 26. The control population received weekly counseling from a registered dietitian for the first 8 weeks, then monthly for the rest of the study.
Weight loss at 4 weeks served as the primary endpoint. Change in body composition, biomarkers of metabolic disorders and cardiovascular risk, and quality of life served as secondary endpoints.
‘Dramatic’ results
Participants had a median baseline weight of 98 kg, or about 216 pounds.
Men in the intervention arm had significantly greater mean weight loss at 4 weeks (3.9 kg vs. 1.3 kg; P < .001), 8 weeks (5.3 kg vs. 1.6 kg; P < .001) and 26 weeks (6.1 kg vs. 2.5 kg; P = .002).
“They are dramatic [differences],” Nanus said. “One of the striking things about the study is that weight loss was sustained after ending the home-delivered meals. Patients lost weight, and they continued to lose weight in the treatment arm.”
Nanus hypothesized the coaching had the greatest impact.
“It’s that coaching that really educates you about how you should eat, and that makes a big difference in how these patients did,” he said.
Researchers also observed significant differences in dual-energy X-ray absorptiometry measures.
Men who received the whole-food plant-based diet had significantly improved BMI at 1 month (–1.1 kg/m2 vs. 0.36 kg/m2; P < .001) and 6 months (–1.78 kg/m2 vs. –0.18 kg/m2; P < .005), and total mass at 1 month (–3.61 vs. –0.93; P < .001) and 6 months (–6.29 vs. –2.54; P = .001).
They also had significantly improved fat mass at 6 months (–3.8 vs. –0.93; P < .001).
Men in the intervention arm lost significantly more lean mass in the first month (P = .006) but that became nonsignificant at 6 months.
“This really shows that this approach to dieting is the correct approach,” Nanus said. “You’re going lose some [lean mass] initially and that’s not the best thing to lose, but over time, you’re just losing fat mass. You don’t see that in the control. You just don’t see the same decrements in the control arm.”
Nanus and colleagues plan to publish more data in the future on inflammatory markers, stool and serum metabolome, and stool microbiota to further define the impact of a whole-food plant-based diet.
Nanus also would like to investigate whether GLP-1s have the same impact as a whole-food plant-based diet.
“It’s a lot easier to lose weight if you just inject yourself,” he said. “It would be interesting to see if you take one of those drugs, do your inflammatory markers go down? Do your metabolomics change? Do your stool microbiota change?”
For more information:
David M. Nanus, MD, interim chief of the division of hematology and medical oncology and Mark W. Pasmantier Professor of Hematology and Medical Oncology in Medicine at Weill Cornell Medicine, can be reached at dnanus@med.cornell.edu.
Sources/Disclosures
Source:
Jacobs N, et al. Abstract 5098. Presented at: ASCO Annual Meeting; May 29-June 2, 2026; Chicago.
Disclosures:
Nanus reports consulting or advisory roles with Genentech/Roche, Janssen Oncology and Telix Pharmaceuticals, and research funding from Exelixis and Zenith Epigenetics.
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