Food and sleep often come up in assessment, not because they explain every mental health difficulty, but because they are part of everyday life. A person may notice that worries feel louder after several poor nights, that caffeine makes their body feel uncomfortable, that eating has become rule bound, or that tiredness makes it harder to manage routines. These are observations to explore, not proof of a cause. A blog cannot determine whether a pattern of eating, sleep, intrusive thoughts or anxiety is OCD, an eating disorder, a sleep disorder, a physical health issue or another difficulty. Sleep and appetite can be affected by stress, medication, hormones, illness, pain, shift work, caring, trauma, mood and many other factors. New, changing or worrying symptoms should be discussed with an appropriate medical professional rather than treated as a lifestyle problem. Questions about meals, caffeine, sleep and daily rhythm can help someone describe the wider context of their distress. They should not become a prescription to follow a particular diet, cut out food groups, stop medication or force a sleep routine. For some people, detailed tracking itself can increase anxiety or compulsive checking. Assessment can explore what is helpful, what feels safe and whether specialist medical, nutritional or psychological support is needed. CBT may be considered where appropriate, but it is not dietary advice or an OCD diagnosis. If behavioural experiments are used, they are planned collaboratively with a qualified clinician after assessment, consent and attention to health and any eating related risk. Exposure based work should never be self directed from an article. If food or sleep concerns involve severe restriction, purging, rapid weight change, fainting, self harm thoughts, crisis or an inability to keep yourself safe, urgent appropriate help is needed. For related information, see CBT support for OCD at lyceumclinic.co.uk/therapy/ocd/, the intrusive thoughts guide at lyceumclinic.co.uk/guides/cbt for ocd intrusive thoughts/ and body image, weight and wellbeing at lyceumclinic.co.uk/guides/mental health weight diet movement/. The Lyceum Clinic offers assessment led CBT online and in West London.