Dr. Isabel Viña on training on an empty stomach: "If you go with a heavy stomach, you lose the benefits of exercising."

To train on an empty stomach or not? This is one of the most common questions among those starting to take care of their health and body. That's why Isabel Viña, an endocrinology specialist and social media influencer, wanted to answer this question in a video shared on her TikTok account, where she has thousands of followers interested in learning.

Viña starts with a key reflection: “How are you going to train?” Beyond theoretical recommendations, the expert emphasized the importance of listening to your body and adapting your routine to your individual needs. "If, by telling you it's best to eat protein and carbohydrates two hours before training, you do it, but you end up with a heavy stomach and the urge to vomit, we've lost the whole point of sports," she explained in her presentation.

Far from suggesting a single, valid formula, the expert emphasized that there are multiple ways to train with benefits, and that it doesn't make sense to follow a nutritional strategy if it means giving up exercise due to discomfort. "The important thing is exercising. The rest adds up, yes, but if trying to do it perfectly means you're going to stop exercising, then we're missing the point of it all," she concluded in her video.

At the same time, Viña clarified that training on an empty stomach doesn't necessarily mean being energy-depleted. In fact, she emphasized that the body has eaten a meal the night before, and therefore, "muscle glycogen stores will be full." She also pointed out in the video that amino acids continue to circulate in the body for several hours, which can help sustain physical activity.

However, the doctor placed special emphasis on the post-exercise period: it's essential to replenish nutrients. "After training, make sure you recover well with protein and carbohydrates," she recommended. This way, the body can repair damaged muscle fibers and replenish its glucose reserves, both in the liver and muscles.

Science supports fasting exercise

Isabel Viña's recommendations are not only based on her clinical experience but also supported by scientific research. A recent study published in the journal Clinical Nutrition ESPEN showed that exercising on an empty stomach increases fat oxidation during physical activity compared to exercising after eating.

This effect translates into greater use of lipids as an energy source, although researchers caution that this does not guarantee greater long-term weight loss, as the body tends to compensate at other times of the day, reducing its energy expenditure.

Furthermore, a systematic review published in Nutrients concluded that fasted aerobic training can improve insulin sensitivity and promote greater fat burning. These effects could be especially beneficial for people with insulin resistance or at risk of developing type 2 diabetes, making this strategy a potential tool in the prevention of metabolic diseases.