One of the most consumed fish in Portugal is generating controversy after a doctor in Spain claimed that it is so nutritious that it could “endure” a person for a month, an idea that quickly went viral. The fish mentioned by the doctor in question is sardines, considered one of the most complete foods due to the combination of protein, omega-3 and micronutrients.
The idea was publicized by the Spanish newspaper 20minutos, which quotes doctor Jorge García-Dihinx and points to this fish as a “superfood” due to the combination of macronutrients and micronutrients.
However, from a public health point of view, it is important to separate what is a “viral” message from what is safe dietary advice: sardines may be an excellent choice, but living on just one food raises nutritional and clinical doubts.
What is being said, and why it went viral
The starting point is simple: the doctor states that sardines offer protein, omega-3 and several vitamins and minerals, and refers to the experience of researcher Nick Norwitz, who publicly reported a very high consumption of sardines for 30 days.
Norwitz shared results on video and social media, including changes in markers like the “omega-3 index,” which helped amplify the “eating sardines as a shortcut” narrative for metabolic benefits.
But it is important to remember one detail: individual experiences do not replace clinical recommendations or robust studies on the safety and nutritional adequacy of restrictive diets for the general population.
Are sardines healthy? Yes, and there are objective reasons
Sardines (fresh or preserved) are a fatty fish with recognized nutritional value: they tend to be a good source of protein, omega-3 (EPA/DHA) and nutrients such as vitamin B12, calcium and vitamin D (especially when the bones are consumed, in the case of preserves).
This profile explains why they are often linked to cardiovascular benefits and bone health, in the context of a balanced and varied diet.
Still, “being very nutritious” does not mean “being enough for everything”: the quality of a diet also depends on the diversity of foods, fibers, vitamins and compounds present in fruits, vegetables and whole grains.
Experts’ warning: a “single” food is not a dietary plan
According to , experts have warned that diets based on a single food can lead to imbalances and deficiencies, even when the food chosen is healthy, and that there is no evidence to support this type of strategy as a safe way to eat for weeks.
In the specific case of sardines, there are also practical points: many canned foods contain salt (which may be relevant for those controlling blood pressure), and frequent consumption of fish may require attention to guidelines on variety and exposure to contaminants, especially in vulnerable groups.
The rule that continues to make the most sense is simple: use sardines as an ally, not as a “single diet”. For major changes in diet, especially with chronic illnesses or medication, the most prudent thing is to speak to a healthcare professional (doctor or nutritionist).
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