Certified LEAP Therapist Nutritionists and Dietitians in Phoenix, AZ

Are your stomach issues controlling your life? Perhaps you have been diagnosed with IBS (Irritable Bowel Syndrome) or SIBO, or given no diagnosis at all. Have you tried probiotics and other natural remedies, but nothing has worked? And after countless doctor visits and google searches, you’re frustrated and discouraged? I get it. I’ve been there, as have so many of my clients. I'm Alyssa Simpson, a Functional Nutritionist, Registered Dietitian, and Certified Gastrointestinal Nutritionist specializing in digestive issues. I’m dedicated to resolving the root cause of your troubling symptoms — not just giving you a temporary fix.
Are your stomach issues controlling your life? Perhaps you have been diagnosed with IBS (Irritable Bowel Syndrome) or SIBO, or given no diagnosis at all. Have you tried probiotics and other natural remedies, but nothing has worked? And after countless doctor visits and google searches, you’re frustrated and discouraged? I get it. I’ve been there, as have so many of my clients. I'm Alyssa Simpson, a Functional Nutritionist, Registered Dietitian, and Certified Gastrointestinal Nutritionist specializing in digestive issues. I’m dedicated to resolving the root cause of your troubling symptoms — not just giving you a temporary fix.

Did you just get diagnosed with Gestational Diabetes and you are overwhelmed and upset and don't know where to begin? Do you struggle with constant fatigue and find it difficult to keep up with mom duties? Is it hard to know what to eat and prepare for your family? Do you want to have energy throughout your pregnancy? Aim To Thrive Nutrition is here to support YOU in being all you want to be by conducting virtual appointments (yep you can do it for anywhere). Come THRIVE with us!
Did you just get diagnosed with Gestational Diabetes and you are overwhelmed and upset and don't know where to begin? Do you struggle with constant fatigue and find it difficult to keep up with mom duties? Is it hard to know what to eat and prepare for your family? Do you want to have energy throughout your pregnancy? Aim To Thrive Nutrition is here to support YOU in being all you want to be by conducting virtual appointments (yep you can do it for anywhere). Come THRIVE with us!

My ideal client knows that personalized nutrition plans are the best plans of attack. For five years, I implemented a test-do n't-guess strategy and never looked back. I help my clients overcome issues of fatigue, weight loss resistance, GI upset, depression, insomnia, and more by taking a root cause functional medicine approach, implementing lifestyle, nutrition, and more.
My ideal client knows that personalized nutrition plans are the best plans of attack. For five years, I implemented a test-do n't-guess strategy and never looked back. I help my clients overcome issues of fatigue, weight loss resistance, GI upset, depression, insomnia, and more by taking a root cause functional medicine approach, implementing lifestyle, nutrition, and more.
More Dietitians and Nutritionists Nearby

Joy Lynn Umphrey
Nutritionist/Dietitian, MDA, RDN, LDN, CLT
Verified Verified
1 Endorsed
Online Only
I help my clients get relief from GI issues such as diarrhea and/or constipation, bloating, abdominal pain, joint pain, and migraines by incorporating both food sensitivity testing and a low FODMAP diet. I also work with women who have hypothyroidism, a family history of diabetes or have had gestational diabetes to learn how to become their healthiest best self.
I help my clients get relief from GI issues such as diarrhea and/or constipation, bloating, abdominal pain, joint pain, and migraines by incorporating both food sensitivity testing and a low FODMAP diet. I also work with women who have hypothyroidism, a family history of diabetes or have had gestational diabetes to learn how to become their healthiest best self.
Certified LEAP Therapist Nutritionists and Dietitians
What is a Certified LEAP Therapist?
A Certified LEAP Therapist (CLT) is a dietitian who has received specialized training in food sensitivity and chronic condition management. They complete the LEAP (Lifestyle Eating and Performance) program, which focuses on identifying and managing food sensitivities to alleviate chronic conditions. CLTs are trained to use the Mediator Release Test (MRT), a blood test that measures inflammatory responses to various foods. This allows them to create individualized dietary plans tailored to each client's specific sensitivities and chronic health issues. By identifying and eliminating trigger foods, CLTs help clients reduce inflammation and manage chronic condition symptoms more effectively.
Who should work with a Certified LEAP Therapist?
Certified LEAP Therapists (CLTs) primarily work with clients who have chronic conditions or food sensitivities that may benefit from dietary modifications. These conditions include irritable bowel syndrome (IBS), Crohn’s disease, ulcerative colitis, fibromyalgia, rheumatoid arthritis, and polycystic ovary syndrome (PCOS). Many clients turn to CLTs when other interventions have failed or when they desire additional strategies to improve their symptoms beyond medication and conventional treatments. By tailoring diets to individual needs, CLTs help clients manage their conditions more effectively and enhance their overall quality of life.
What happens in a LEAP Therapy session?
The overall goal of LEAP Therapy is to help clients identify foods that may be triggering their symptoms and guide them through an elimination diet followed by a reintroduction phase. LEAP Therapy typically begins with the administration of a Mediator Release Test (MRT), which categorizes food sensitivities from "green" (non-reactive) to "red" (highly reactive). Based on these results, dietitians work with clients to create a diet plan that eliminates highly reactive foods while still promoting overall health and balance. Additionally, LEAP dietitians often advise clients on other lifestyle modification strategies, such as incorporating more anti-inflammatory foods (such as fruits, vegetables, and certain spices) into their diet.
What is the LEAP elimination diet?
The LEAP elimination diet is designed to help individuals identify specific foods that may be causing intolerance symptoms or contributing to chronic disease symptoms. When it is unclear which foods are triggering these issues, the LEAP elimination diet systematically removes and then reintroduces foods to identify specific triggering foods. This process often follows the completion of the Mediator Release Test (MRT), which offers insight into which foods might be problematic. By eliminating and reintroducing foods based on MRT results, clients can better understand their triggers and manage their symptoms more effectively.