Diarrhea following a meal, particularly when it occurs in conjunction with other gastrointestinal symptoms such as nausea, vomiting, or abdominal cramping, can indeed be indicative of food poisoning. Food poisoning is typically caused by consuming food or beverages contaminated with infectious agents, including bacteria (such as Salmonella, E. coli, or Campylobacter), viruses (such as norovirus), or parasites.

Given that your symptoms began shortly after dining out, it is plausible that you may have ingested contaminated food or water. The timing of symptom onset can vary depending on the causative agent. For instance, symptoms from bacterial toxins, such as those produced by Staphylococcus aureus, can appear within a few hours, whereas other bacterial infections might take longer to manifest.

Here are some considerations and steps you might take:

1. Hydration: Ensure adequate fluid intake to prevent dehydration, which is a common complication of diarrhea. Oral rehydration solutions or electrolyte-rich fluids can be beneficial.

2. Dietary Adjustments: Consider a bland diet, avoiding dairy, caffeine, alcohol, and fatty or spicy foods until symptoms improve.

3. Symptom Monitoring: Keep track of any additional symptoms, such as fever, blood in stools, or severe abdominal pain, which could indicate a more serious condition requiring medical attention.

4. Duration and Severity: If diarrhea persists beyond a few days, or if you experience severe symptoms, it would be prudent to consult a healthcare professional. They may recommend stool tests to identify the specific pathogen and guide appropriate treatment.

5. Preventive Measures: Reflect on food safety practices to prevent future occurrences, such as ensuring proper food handling, cooking, and storage.

While food poisoning is a common cause of acute diarrhea, other potential causes should also be considered, such as viral gastroenteritis or a reaction to a new food or medication. If your symptoms are severe or persistent, seeking medical evaluation is advisable to rule out other conditions and to receive tailored treatment.