A man who set out to avoid protein for 30 days was forced to stop after just 10 days when the effects on his body became too difficult to ignore.
Manuel Enrique Marin Colorado took on the challenge to see what would happen if he removed protein from his meals entirely, but he quickly discovered just how restrictive and unpleasant that would be.
Because protein appears in so many everyday foods, finding suitable options became a struggle almost immediately. Even foods not usually thought of as protein sources contain some amount, such as watermelon with 0.6g per 100g and dark chocolate with around 5g per 100g. As a result, Manuel even turned to candy before workouts just to get some energy in.
For context, the recommended dietary allowance (RDA) for protein is 0.8 grams per kilogram of body weight per day for healthy sedentary adults, though many health organizations recommend higher intakes for optimal health and muscle maintenance.
Manuel explained:
“Protein is in everything now, water, snacks, literally every food has a ‘protein version.’ I wanted to see what would actually happen if I cut it out completely instead of just cutting back.”
Before starting, he spoke with his doctor, who warned him that his body would “try eat its own muscles”.
To stick to the plan, Manuel relied on foods that contained no protein at all, including zero-protein sourdough bread, olive oil, vegan cheese and butter.
He said the first day went reasonably well, but by day 10 the experiment had taken a serious turn. Manuel became physically ill after eating what he described as some of the worst food he had ever consumed.
“My workouts got weaker every day, I stopped looking in the mirror, my physique started breaking down, and my brain didn’t even feel like mine anymore,” he said of the impact of having no protein had on him.
After getting sick, he chose to end the challenge early. According to the body metrics he checked after day 10, he had lost 0.3 kilos of muscle and reduced his body fat by 1.1 percent.
Medical experts note that when protein intake is severely restricted, the body breaks down muscle tissue to obtain the amino acids it needs for essential functions. Symptoms of acute protein deficiency can include muscle weakness and wasting, fatigue, weakened immune response, and cognitive effects, which aligns with Manuel’s reported experiences during the challenge.
He added:
“I think lifting weights almost every day is the only reason I didn’t lose more muscle,” he told us. “Without training, I don’t think the results would’ve been the same.”
Although the physical effects were severe enough to make him quit, Manuel said the biggest challenge was psychological.
“The hardest part wasn’t physical, it was mental,” he explained. “I was eating such strange food combinations just to hit my calories without protein that it messed with my head more than my body.”
He also made it clear that he does not think others should copy what he did.
“I wouldn’t recommend anyone actually do this, that’s not the point of the video,” he shared. “It’s more about realizing how much protein is pushed into everything, and how important it is to think about the quality and type of protein you eat, not just hitting a number.”
Manuel added:
“If people find this kind of experiment interesting, I’ve got more like it coming, I’m currently documenting a peptide experiment and a series testing intense Korean skincare treatments.”