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Updated: May 27, 2026

One-anastomosis Gastric Bypass (OAGB) in Rats
Published on: November 10, 2018
Case study: nutrition challenges of a marathon runner with a gastric bypass
1Sports Nutrition Services, Healthworks, Chestnut Hill, MA, USA.
Abstract:
A new type of athlete is appearing in the offices of sports dietitians: formerly obese people who have undergone gastric bypass surgery and now aspire to be marathoners, triathletes, and other types of endurance athletes. The standard nutrition advice offered to bypass patients is contrary to the standard sports advice given to athletes. Bypass athletes need to limit carbohydrates, fluids, and energy intake and consume a protein-based diet. This case study describes the sport nutrition concerns of a woman who, after having gastric bypass surgery, trained to run a marathon (42 km). Because of her limited ability to consume food and fluids, she experienced difficulty preventing fatigue and dehydration during her long training runs and the marathon itself. She learned through trial and error how to survive the nutritional challenges and complete the marathon. Health professionals need to be aware of the potential medical risks associated with endurance exercise in gastric bypass patients. Research is needed to determine the best sports nutrition practices for bypass patients. Only then can sport dietitians better educate this small but growing contingent of endurance athletes so the athletes can meet their training and performance goals and reduce their risk of experiencing serious health consequences.
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