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Three generations of women smiling—a grandma, mother and child

Every woman's story deserves to be heard.​

Third Sister offers online & London-based dietitian and nutritionist services for weight loss, PCOS, pregnancy, menopause, IBS, and more. Whether you’re looking for a weight loss nutritionist or need a diet plan for PCOS or menopause, we are here to support your unique journey.

Learn more about our services ⭣
At Third Sister, we go beyond diets to truly understand your story and provide personalised nutrition strategies tailored to your needs. From managing PCOS or IBS to finding sustainable solutions for weight loss in London and beyond, our practice is designed to empower you. With expert support from a weight loss nutritionist and registered dietitian specialising in women’s health conditions, we help you take charge of your health and achieve lasting results.

Ways we can work together

3-month program

6 sessions total. Ideal for those looking for focused, short-term support.

Includes:
  • 60-90 minute in-depth initial assessment
  • Personalised diet plan and program roadmap, including any recommended tests or analyses (additional costs apply for tests)
  • Personalised educational material to empower your health journey
  • 5 x 60-min follow-up sessions*
  • Ongoing 1-on-1 instant messaging or email support during working hours to answer your questions, track your progress, and make any adjustments to your program
  • Shopping list and recipe suggestions
  • Direct communication with other medical health practitioners if needed
*Follow-up sessions are generally recommended every two weeks, but can be taken within 6 months of program start.
12 sessions total. Perfect for long-term transformation and sustained results.​

Includes:
  • 60-90 minute in-depth initial assessment
  • Personalised diet plan and program roadmap, including any recommended tests or analyses (additional costs apply for tests)
  • Personalised educational material to empower your health journey
  • 11 x 60-min follow-up sessions*
  • Ongoing 1-on-1 instant messaging or email support during working hours to answer your questions, track your progress, and make any adjustments to your program
  • Shopping list and recipe suggestions
  • Direct communication with other medical health practitioners if needed

*Follow-up sessions are generally recommended every two weeks, but can be taken within 6 months of program start.
12-24 sessions total. Tailored for anyone looking to start or already taking weight loss medication

Includes:
  • 60-90 minute in-depth initial assessment
  • Personalised diet plan based on medication protocol
  • Roadmap for support during medication phase, transition off the medication and long-term weight loss maintenance without medication
  • Recommended tests or analyses (additional costs apply for tests)
  • Personalised educational material to empower your health journey
  • 11-23 x 60-min follow-up sessions*
  • Ongoing 1-on-1 instant messaging or email support during working hours to answer your questions, track your progress, and make any adjustments to your program
  • Shopping list and recipe suggestions
  • Direct communication with other medical health practitioners

*Follow-up sessions are generally recommended every two weeks, but can be taken within 6 months of program start.
Suitable for existing clients who want to discuss any updates or changes to their health status, and want to make modifications to their current plan.​

Includes:
  • 1 x 60-minute follow-up session
Enquire now
Clementine Vaughan, nutritionist and dietitian in London specialising in weight loss, PCOS, menopause, IBS, and more.

3-month program

6 sessions total. Ideal for those looking for focused, short-term support for weight loss, IBS management, or personalised diet plans for PCOS, menopause or other hormonal issues.​

Includes:
  • 60-90 minute in-depth initial assessment
  • Personalised diet plan and program roadmap, including any recommended tests or analyses (additional costs apply for tests)
  • Personalised educational material to empower your health journey
  • 5 x 60-min follow-up sessions*
  • Ongoing 1-on-1 instant messaging or email support during working hours to answer your questions, track your progress, and make any adjustments to your program
  • Shopping list and recipe suggestions
  • Direct communication with other medical health practitioners if needed

*Follow-up sessions are generally recommended every two weeks, but can be taken within 6 months of program start.

Enquire now
Third Sister's founder and registered dietitian Clementine Vaughan demonstrating nutritious food prep to women

6-month program

12 sessions total. Perfect for long-term transformation, including sustained weight loss or symptom management for PCOS, IBS, menopause, and more.​

Includes:
  • 60-90 minute in-depth initial assessment
  • Personalised diet plan and program roadmap, including any recommended tests or analyses (additional costs apply for tests)
  • Personalised educational material to empower your health journey
  • 11 x 60-min follow-up sessions*
  • Ongoing 1-on-1 instant messaging or email support during working hours to answer your questions, track your progress, and make any adjustments to your program
  • Shopping list and recipe suggestions
  • Direct communication with other medical health practitioners if needed

*Follow-up sessions are generally recommended every two weeks, but can be taken within 6 months of program start.

Enquire now
Clementine Vaughan, nutritionist & dietitian speaking to a weight loss client

Medicalised weight loss support

12-24 sessions total. Tailored for anyone looking to start or already taking weight loss medication.

Includes:
  • 60-90 minute in-depth initial assessment
  • Personalised diet plan based on medication protocol
  • Roadmap for support during medication phase, transition off the medication and long-term weight loss maintenance without medication
  • Recommended tests or analyses (additional costs apply for tests)
  • Personalised educational material to empower your health journey
  • 11-23 x 60-min follow-up sessions*
  • Ongoing 1-on-1 instant messaging or email support during working hours to answer your questions, track your progress, and make any adjustments to your program
  • Shopping list and recipe suggestions
  • Direct communication with other medical health practitioners

*Follow-up sessions are generally recommended every two weeks, but can be taken within 6 months of program start.

Enquire now
Online consultation with a weight loss nutritionist and dietitian in London

Add-on sessions

Suitable for existing clients who want to discuss any updates or changes to their health status, and want to make modifications to their current custom diet plan.

Includes:
  • 1 x 60-minute follow-up sessions

Enquire now

Our Process

1 - Initial Assessment

Every program at Third Sister begins with an in-depth, 60-90 minute initial assessment, entirely free of charge. Whether you decide to commit to a program or not, you will get to experience what it’s like to work with us. You can book your initial assessment via the booking platform or via email. Once your booking is confirmed, you will receive a short intake form to fill out prior to your assessment call.

2 - Health History & Goal Setting

During this initial assessment, we will go through your health history, goals, and conditions such as weight loss, PCOS, IBS, menopause. We will also assess the potential need for a current diet analysis (for nutritional completeness) and/or further blood tests. I will provide some initial diet and lifestyle recommendations centred around clinical dietetics, but also informed by other practices such as nutrition, functional medicine, behavioural therapy, naturopathy and modern medicine. I will also share a potential roadmap for our work together.

3 - Program Initiation & Personalised Recommendations

If you decide to move forward with one of the programs, our real work will begin with a comprehensive, personalised diet plan for you to follow.

4 - Follow-up & Ongoing Support

We recommend regular follow-up sessions once every 2 weeks to keep you accountable. You will also receive ongoing 1-on-1 support via email and messaging on the client portal during working hours (9am-6pm GMT).

Have more questions about working with Third Sister?

Check out our FAQs or contact us.
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