Irritable Bowel Syndrome (IBS): The patient's symptoms of loose, frequent stools after meals without abdominal pain, nausea, vomiting, or blood in stool, and the temporal relationship with an episode of significant anxiety, suggest IBS. The resolution of anxiety without improvement in symptoms does not rule out IBS, as it can be exacerbated by stress.

Functional diarrhea: Characterized by frequent, loose stools without an identifiable cause, which fits the patient's presentation. The absence of abdominal pain and other symptoms makes inflammatory or infectious causes less likely.
Lactose or fructose malabsorption: Although the patient does not report acidic stools, malabsorption of lactose or fructose could lead to similar symptoms. Dietary habits and potential recent changes could be contributing factors.
Small intestine bacterial overgrowth (SIBO): Could be considered given the postprandial nature of the symptoms, although the absence of bloating and abdominal pain makes it less typical.

Inflammatory bowel disease (IBD): Although less likely due to the absence of abdominal pain, blood in stool, and systemic symptoms, IBD (Crohn's disease or ulcerative colitis) must be considered due to its potential severity and need for early intervention.
Colorectal cancer: Though rare in a 41-year-old without a family history or other risk factors, any change in bowel habits warrants consideration of colorectal cancer, especially if symptoms persist.
Infectious diarrhea: Despite the duration of symptoms and lack of systemic symptoms like fever, an infectious cause could still be present, particularly if the patient has been exposed to someone with a similar illness or has recently traveled.

Thyrotoxicosis: Hyperthyroidism can cause changes in bowel habits, including diarrhea, although it would typically be accompanied by other systemic symptoms such as weight loss, palpitations, and heat intolerance.
VIPoma or other neuroendocrine tumors: These rare tumors can cause severe, watery diarrhea, but the patient's symptoms do not perfectly align, and other systemic symptoms would likely be present.
Celiac disease: An autoimmune reaction to gluten, leading to small intestine damage and potentially causing diarrhea among other symptoms. However, the onset in adulthood without other suggestive symptoms makes this less likely.