After researching this claim, I found that it is false. A large body of scientific research shows that diet can affect mood, stress levels, and mental health outcomes. While food alone is not the sole cause of mental health conditions, nutrition plays a meaningful role in brain function and emotional regulation. The claim ignores well-established connections between diet, brain chemistry, and mental well-being.
Harvard Medical School explains how diet affects brain structure, neurotransmitters, and inflammation, all of which influence mood and mental health. This source shows that what people eat can contribute to symptoms of depression and anxiety. https://www.health.harvard.edu/blog/diet-and-depression-2018022213309
BBC Future summarizes scientific findings on how food affects mood, energy, and stress, making the research easier to understand without oversimplifying it. https://www.bbc.com/future/article/20200401-how-food-affects-your-mood
Medical and psychological organizations aim to promote public health, which may emphasize lifestyle factors like diet. However, these sources rely on peer-reviewed studies and do not claim that food alone determines mental health, which adds credibility to their conclusions.
There is little credible evidence supporting the idea that food has no impact on mood or mental health. At most, some sources argue that diet is only one factor among many, but not that it has zero effect.
Multiple studies show that diet affects brain chemistry, inflammation, and gut health, all of which are linked to mood and mental health. Research consistently finds associations between poor diet and higher rates of depression and anxiety, which directly contradicts the claim.
This claim appears to be a general statement shared online rather than coming from a specific individual or organization, so there was no clear original source to contact.