BMI and Foundayo: check your number and what it actually means

Last verified: 12 August 2026

The exact UK criteria for Foundayo

The MHRA has licensed Foundayo, alongside a reduced-calorie diet and increased physical activity, for adults with:

• a BMI of 30 or above (obesity), or
• a BMI between 27 and 30 (overweight) plus at least one weight-related condition.

It's separately licensed to improve blood sugar control in adults with insufficiently controlled type 2 diabetes. Weight-related conditions that typically qualify in UK GLP-1 prescribing include type 2 diabetes, prediabetes, high blood pressure, abnormal cholesterol, obstructive sleep apnoea and cardiovascular disease. The prescriber's assessment, not a list on a website, is what decides your case; a proper consultation also screens the things a calculator never can, like your medical history, other medicines and the thyroid red flags.

Lower thresholds for some ethnic backgrounds

BMI underestimates health risk at a given weight for people from some ethnic backgrounds. UK NICE guidance uses lower thresholds for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background, because conditions like type 2 diabetes develop at lower BMIs in these groups. In practice, thresholds around 2.5 points lower are used. If that's you, don't rule yourself out at a BMI of 28 or 29 without asking: raise it in your consultation, because a good prescriber will apply the adjusted thresholds.

What BMI genuinely can't tell you

Time for the honest bit. BMI is a blunt instrument: it can't tell muscle from fat, so a rugby player and an inactive person can share a number while having completely different health; it says nothing about where fat sits, and waist measurement often predicts risk better; and it was built from population averages, which is why it needs the ethnic adjustments above. None of that makes it useless. It's quick, free, consistent, and at population scale it tracks health outcomes well, which is why licences and guidelines are built on it. The sensible reading: treat your BMI as one signal that starts a conversation, alongside waist size, blood pressure, blood sugar and how you actually feel, and let a clinician put the picture together.

Helpful extras worth knowing

• Waist check: as a rule of thumb, a waist over half your height suggests carrying risk around the middle, whatever your BMI says. A tape measure is the cheapest health tool you'll ever buy.
• Your BMI moves, and so does eligibility maths. Prescribers assess you at the point of prescribing; ongoing treatment reviews are normal as your weight changes.
• Travel insurance asks for BMI too. Medical screenings routinely ask current height and weight, and honesty matters because claims can be checked against records. Our travel guide covers it properly.
• NHS BMI tools: the NHS BMI calculator includes the ethnic adjustments and links to NHS weight management support, which is free and worth knowing about whatever you decide on medication.
• Beware quiz-only prescribing. A BMI typed into a form is not a consultation. Reputable providers verify identity and weight, review your history and give you a real clinician to talk to; that's part of how you spot the good ones.