This is a randomised trial in which healthy volunteers, men and women aged 50-75 years from the general community are randomized into one of three arms: participants will be provided with 50 gm extra virgin coconut oil,or 50 grams butter or 50 extra virgin olive oil to be eaten daily for a month. The key outcome is blood low density lipoprotein cholesterol concentrations and secondary outcomes blood lipid profile (total cholesterol, high density lipoprotein cholesterol, triglycerides) and anthropometric measures: weight and waist circumference. This trial is powered to detect a difference of 0.5 mmol/L LDL-cholesterol difference between the trial arms.

This is a randomized trial in which healthy volunteers from the general community are randomized into one of three arms: consumption of 50 gm of extra virgin coconut oil daily OR 50gm of butter daily OR 50gm of extra virgin olive oil daily (50gm is about 2 ounces, or 2 table spoons), to be consumed over a one month period.

The research participants will be recruited from the general community through advertising (BBC).

After full informed consent, participants will attend an assessment visit and have a baseline measures of weight, height, waist circumference, blood pressure, a blood sample for assessment of blood lipids and other metabolic markers, and fill in a health questionnaire and dietary questionnaire. Participants will be randomly allocated to one of three arms: coconut oil, butter or olive oil and will be given supplies of these (portioned, or with measuring spoons) with information about daily consumption of 50 gram of one of these fats.

After one month, participants will return for follow up assessment which will include a repeat blood sample, anthropometric measures and blood pressure, and questionnaire.

Blood samples collected by venepuncture will be stored at the University of Cambridge and analysed at the Department of Clinical Biochemistry, Cambridge University Addenbrooke's Hospital.

At the end of the study, all participants will be given the individual participant results of the anthropometric measures and lipid profiles at baseline and follow up as well as the overall findings of the trial.

Inclusion Criteria:

• Willing to participate in the trial of dietary interventions for one month within the age range

Exclusion Criteria:

• No known cardiovascular disease: heart disease or stroke; no known cancer; no known diabetes; no use of lipid lowering medication eg. statins; no contraindications to high fat diet e.g. gall bladder or other gastrointestinal condition

Anonymised IPD data from the trial will be available at the end of the study with publication of the results, through contact with the principal investigator

Once trial report published; anticipated March 2018

Bona fide researchers

The primary outcome will be blood LDL-cholesterol, secondary outcomes, lipid profile which will be measured in a biochemistry lab by individuals who have no knowledge of the allocation to intervention arms.