functional nutrition

Sibo Doctor Approved
Alyssa Simpson RD, CDE, CLT
Alyssa Simpson

(602) 422-9800

Sibo Doctor Approved
certified gastrointestinal nutritionist
Sibo Doctor Approved
certified gastrointestinal nutritionist

Success Stories

GERD, Food Allergies/Sensitivities
Jolanta Testimonial
Fatty Liver/Food Sensitivities
Based on 8 reviews
S Tapia
S Tapia
Where do I begin- this had been over a 3 year journey in trying to discover what my mother had been suffering from. She had been struggling with painful bloating, extreme gas/belching, loss of weight (30 pounds) occasional vomiting and not been able to eat anything without pain. At her most extreme with this condition- she was not able to even eat a piece of toast without suffering from extreme bloat and severe pain. I had been at my wits end in attempting to find a specialist who would really listen to her and understand what she was dealing with was actually true! The four different G.I specialist I had taken her to sent her for all tests related to the stomach region ( and I mean all- even duplicate tests). I finally found an amazing G.I. specialist who really listened to her and her symptoms and diagnosed her with having SIBO. The specialist stated he was only a single part of her journey to recovery. He recommended, in order to fully overcome her condition, she would need to consult with a nutritionist/dietitian. So, with that said, she began her journey with Alyssa Simpson. From the beginning, Alyssa provided reassurance that she would overcome SIBO, she was not the only one, and would be able to once again eat without pain. Alyssa has an overwhelming amount of knowledge in supplements and proper diet/food to follow to assist in her recovery process. Alyssa was available to answer all questions and immediately provided other options for supplements and food when needed. Throughout my mother’s journey, she slowly began noticing the ability to eat without suffering from discomfort and began gaining weight once again. My mother finally was able to see the light at the end of the tunnel with Alyssa’s help. Now, after eight months following with Alyssa, my mother is feeling great and eating as she once did before her condition. I cannot thank Alyssa enough for all that she has done for my mother.
Cynthia Holly
Cynthia Holly
I came to Alyssa desperate for help with my digestive disorder. She listened, worked with me to find the right supplements and diet to help repair my gut. I did not realize how sick I was until I wasn't. I highly recommend Alyssa Simpson and the help she offers.
Pete Owens
Pete Owens
After months of getting nowhere with my PP and GI I was referred to Alyssa. Any skepticism I had quickly dissipated. We developed a plan to not just alleviate my symptoms, but correct the problem and improve my overall gut health. If my issues recur I will absolutely contact Alyssa. She is incredibly knowledgeable and wonderful to work with.
Scott Salisbury
Scott Salisbury
I have had the pleasure of working with Alyssa twice. The second adventure was to narrow down my gut issues and we found out that I had SIBO. Alyssa had a targeted approach to the testing, review, and plan to help get me back on track. I followed all her instructions and even did the elemental diet for a full month (as brutal as it was, it was what I needed). I am happy to report that all her suggestions, supplements and game plan worked. I have not felt this good (GI wise) in several years. I have suffered with GI issues since 2019 and now in 2023 going into 2024, I can get back to living my life going out to eat with friends, having amazing food back in my diet. I have referred Alyssa to a few friends and will continue to do so. Thanks for all your help getting my microbiomes back to a happy state.
Marilyn Banta
Marilyn Banta
Very effective in helping me heal from IBS/Sibo. Easy to work with and very knowledgeable. Thank you.
Alyssa came into my life at the exact moment I needed her. She was a nonjudgemental wealth of knowledge that I needed. I was battling chronic diarrhea and was overweight. Alyssa helped me tackle one issue at a time, one step at a time. Now I'm a much healthier eater, I regularly exercise and my lab results this year impressed my doctors.
Jan Then
Jan Then
I finally got an answer! I have suffered with G.I. problems for at least 10 years and have gone to a number of G.I. doctors searching for the reason I had such problems. They would all say that I had IBS and try to ind out what food was causing it. That was like looking for a needle in a haystack. My last G.I doctor said I think this nutritionist, Alyssa Simpson, might be able to help you. I was willing to try anything at this point. I told her that I had a gluten sensitivity but even after not eating gluten I still had terrible problems. She said I think we will start with a stool sample and go from there. It was quite an in depth test that told her quite a lot. When she said I had parasites then I knew that was a beginning to getting my health back. She put me on detox supplements and we did follow up tests. I learned a lot from her about what foods to eat and what could be possibly causing all of my IBS. I told the doctor she was very good at her job and I wouldn't be feeling as good as I am if it weren't for her. I wouldn't hesitate in a minute to go to her if you want to get help to solve your IBS problems. If you have questions along the way she gets right back to you so you don't feel like you are in this all alone. Thank you Alyssa for all of your help and support.
Joan Stempski
Joan Stempski
Alyssa - I wanted you to know that I am still using the online tracker watching my carbs, fat and protein daily and I am happy to report that my A1C is staying at 5.6 which is in the 'normal' range. It had been 5.7 for many years (which is pre-diabetic) so I am thrilled!! Thanks for your patience and expertise. Joan Stempski

Food Preparation, Healthy Eating

When I came to work with Alyssa, I was on a slippery slope falling down into an unhealthy abyss. I was depressed about the diagnosis from the doctors and discouraged about myself and my ability to change. I had tried Weight Watchers and diets pill but I told Alyssa I didn’t want to be on a dieting roller coaster any more. I knew I was stuck in a world of unhealthy eating.

I never thought I would be good at meal planning and food prep, but after working with Alyssa, I’ve mastered that. I’ve made changes I’ve been able to sustain, and Alyssa gave me the tools I needed to make smart, healthy choices for myself. I can even keep up with my husband!

Alyssa is excellent at helping people find what works for them. She gave me choices and options to help me figure out what works for me. I would tell anything thinking about working with Alyssa just do it! It will change your life.”

Joantha Guthrie

Gastritis, Fibromyalgia, Migraine, & Sinus Issues

I was only expecting my stomach/gut to heal, but what I have experienced is beyond anything I thought was possible.”

I originally came to Alyssa for my stomach pain, although I also suffered from fibromyalgia, migraines, and sinus issues. What I have experienced is beyond anything I thought was possible. 

I started my path with Alyssa, and within two weeks into the program the stomach pain and migraines had diminished. I have not had a migraine since, and migraines were a weekly occurrence prior to that. Approximately three weeks into my new eating plan, I no longer needed medication for sinus issues. A month later, I was weaned from one of my anti-depressants, and within 3 months, I had completely weaned from the Lyrica that I had been taking for the Fibromyalgia.  I have started working with a personal trainer, and this is the first time I have been able to exercise without extreme muscle pain.

I am beyond ecstatic with the results I have gotten. Plus as an added bonus, I have lost 15 pounds. If you are willing to work this program, Alyssa will patiently walk you through step by step. I have worked with others like Alyssa in the past, however, this is the first time I have had this type of result. Alyssa is an exceptional dietitian, and I have learned a tremendous amount from her, about what and how foods affect my body.

Liz Schultz

Irritable Bowel Syndrome, Barrett’s Esophagus, Parkinson’s 

Prior to beginning my journey with Alyssa, I was experiencing daily bouts of incontinence and severe acid reflux. My IBS is now basically non-existent.”

I went to see Alyssa for a multitude of physical ailments, including early onset Parkinson’s with dementia, IBS, Barrett’s Esophagus, and High Blood Pressure. Prior to beginning my nutrition journey with Alyssa, I was experiencing daily bouts of incontinence and severe acid reflux. My legs were swollen, and I was suffering from daily joint and muscle pain

After about 2-3 weeks into Alyssa’s plan, I started to feel so much better. In just 90 days, the swelling is gone in my legs, by B-12 is finally absorbing to fight my Parkinson’s and dementia, and the new vitamins prescribed by Alyssa are making me feel better overall. My IBS is basically non-existent. The pain & stiffness in my joints and muscles, and my ability to walk improved, and I now have the energy to work out.

I literally feel like Alyssa has given me more years to my life, and has improved the outcome of my progressive illness by helping me to slow down the disease progress. She is very approachable, non-judgmental, and brilliant at what she does. I was so hesitate to open up at first, because others have judged or thought I lacked some type of will power or something. However, I found Alyssa to be accepting and supportive. She is all about solutions and teaching how to use nutrition to repair damage and improve your health.


Irritable Bowel Syndrome, SIBO

My IBS is under control, my weight is down, I have more energy, and I have confidence in my ability to maintain and manage an eating plan that’s right for me.”

I finally reached peak frustration with IBS symptoms I’ve had all my life. I was experiencing chronic constipation, bloating, abdominal distention, water retention, weight gain that wouldn’t budge — general discomfort and frustration that affected my daily life.

Alyssa provided a comprehensive plan that calmed my system down. The combination of an appropriate nutrition plan, sensitivity testing, and SIBO treatment provided tremendous physical, and emotional, relief — it wasn’t my imagination! Something WAS off with my body and the healthy foods I had been eating were making it worse.

Alyssa taught me how to eat healthy for my body and my unique needs, and how to manage any flare ups that may arise. Today I feel much better! I feel healthy from the inside out. My IBS is under control, my weight is down, I have more energy, and I have confidence in my ability to maintain and manage an eating plan that’s right for me.

I have already recommended Alyssa to friends and family with GI and IBS issues. Why? Because she listened and she helped me. She didn’t brush off my concerns. She understood them. She helped me take action that improved my health and my quality of life. I am grateful that my GI doctor referred me to her.


Dennis Testimonial
Chandra Testimonial
Migraine, Food Sensitivities
Rachel Testimonial

Irritable Bowel Syndrome (IBS)

I can go out now without worrying about having to leave early because of my stomach or trying to mask humiliating gas. I have more energy, so I am able to do things and keep up with my family.”

I have suffered from stomach issues for most of my life, and was finally diagnosed with IBS.  It was presented as something I would just have to deal with. I had considerable stomach upset, cramps, gas, and diarrhea. In addition, I was dealing with fatigue that was getting worse as time progressed.  I had no energy to do anything and it affected my mood.  I tried a myriad of medical solutions and medicine.  Nothing alleviated my stomach problems; they just addressed the symptoms once I felt sick.

The longer I have done the program, the better I have felt.  I have identified most of the foods that are an issue for me and how to avoid them.  I can go out now without worrying about having to leave early because of my stomach or trying to mask humiliating gas.  In addition, I am a better mom and wife.  I have more energy, so I am able to do things and keep up with my family. 

My symptoms had been ignored and treated as inconsequential for my entire life. I was used to being brushed off and told that there was nothing that could be done. Alyssa treated me as if she understood and could help.


Irritable Bowel Syndrome (IBS)

Alyssa helped work with me to implement the low FODMAP diet and walked me through each step. I was not only successful but it was easy!”

I was dealing with a lot of symptoms of IBS and knew that dietary changes would help.  I had heard the low FODMAP diet is restrictive so I wanted to have professional guidance. Reading about Alyssa’s experience made me confident that she would be able to help me. 

My IBS was causing daily bloating, abdominal cramping, and frequent bowel movements. I started to deal with nausea which was my push to finally make changes. Going lactose free helped.  I started to cut back on high FODMAP foods but knew I needed to do more.  Alyssa helped work with me to implement the low FODMAP diet. I was so overwhelmed at first after reading up on it but she was amazing in how she walked me through each step. I was not only successful but it was easy.  I feel so much better!!

IBS is now so much more manageable for me!  I go into work now so much more easily instead of dragging myself in like I was doing before due to how I felt. I would definitely recommend others facing similar issues to go see Alyssa! Now that I have identified my trigger foods I no longer feel restricted or overwhelmed, and I am so grateful I did not have to navigate the process on my own.

Sharon R

Irritable Bowel Syndrome (IBS) And Acid Reflux

My stomach pain is gone, my energy level increased dramatically, and my thinking became much clearer and sharper. Alyssa was of far greater assistance to me than any of the doctors I worked with”

I was experiencing a lot of abdominal pain including gas and bloating that would last several hours after I ate.  It was interfering with my quality of life. I had tried Prevacid, antacids, GasX, and using hot water bottles to relieve the pain.

Alyssa ran a test to determine what foods I was sensitive to, and helped me to create a diet that only included foods my body was tolerating well. The results I experience were exactly as I had hoped for.  My stomach pain is gone, my energy level increased dramatically, and my thinking became much clearer and sharper.

Today, I continue to feel terrific.  I am grateful to be able to eat a large variety of foods that no longer bother me and to be able to enjoy my life again. Not only is Alyssa knowledgeable and experienced, but she also has a very warm way about her that allowed me to feel as though I was in very good hands.  She took the time to listen to what was really going on, ask illuminating questions, and explain her recommendations clearly and succinctly.  Alyssa was of far greater assistance to me than any of the doctors I worked with.

Diane Bolden

Blood Sugar Issues

I worked with Alyssa a few years ago on what turned out to be a food sensitivity issue. So when I saw my glucose rising, I decided to consult with her again to gain better balance in the ‘sugar department’. My dad developed type 2 diabetes and I don’t want to go down that path if I can avoid it!  My glucose was in the 114 area & that concerned me.  The only previous treatment I tried was self control & that certainly wasn’t working!! 

Now that the consultations are completed, I feel great – my glucose is at 100 or less (I test it weekly) and I lost a few ‘around the middle’ pounds too!!  If you are reading this, you believe in preventative measures and I feel that consulting with Alyssa is well worth the investment. We only have one body & we need to be better stewards of it.

Joan S

Adrienne Testimonial
SIBO, Gastroparesis
Ali Testimonial
Weight Loss
Kim Testimonial

Irritable Bowel Syndrome (IBS) And Acid Reflux

“I have seen my primary care doctor and a gastroenterologist and was not getting any better.  I have had bloating and uncontrollable diarrhea for over a decade. My body would dump. I woke up after 8 hours of sleep feeling exhausted.  I had tried medications that killed the bad bacteria in the gut, probiotics. Nothing changed.  I am so glad that the gastroenterologist suggested that I see Alyssa. No more bloat, no more embarrassing diarrhea. I wake up feeling refreshed. 

I feel amazing. About 6 weeks into the program I was driving and it hit me that for the first time in more than a decade I felt good. I went to a party recently and people were asking me what diet I was using. I told them that I had stopped eating food that I was allergic to, I wasn’t dieting. I received comment after comment on how good I looked.  I no longer fall asleep in the car. My grandchildren still wear me out, but I enjoy it.  I already have recommended Alyssa to friends.”

Maria Teresa Parks

Irritable Bowel Syndrome (IBS) And Gastroesophageal Reflux Disease (GERD)

After a couple months, my daily diarrhea, bloating, gas, constant abdominal pain, headaches, and fatigue are now gone and I feel better than I did before I became ill!”

After 9 months with intense digestive issues and no solutions from my doctors, I wanted another opinion and a new way of looking for a solution. My symptoms included daily diarrhea, bloating, gas, constant abdominal pain, headaches, and fatigue. I had tried eating gluten free, soy free, dairy free, and low FODMAP.

Alyssa recommended I take the MRT food sensitivity test as well as an extensive nutritional deficiency panel. We created a safe list of foods to start with.  As my gut began to heal, I was able to incorporate more foods into my diet. After a couple of months all my previous symptoms are now gone and I feel better than I did before I became ill!  I feel amazing. I can now eat out again. I can run without losing my breath, and can easily make it through the day without fatigue and pain.

My doctors (3 of them) had all given up trying to find my problem and just wanted to medicate me. Alyssa quickly found and fixed me with no drugs and easy solutions! I have already recommended several people to go see Alyssa!

Ashley W

Overweight And Chronic Health Issues

I lost 27lbs lost over 15 weeks, have developed healthy eating habits, making smart choices and have a better understanding of how to manage my weight and still enjoy life”

I would like to highly recommend Alyssa Simpson for any weight loss/control issues that you may be dealing.  I had significant weight issues, and a high level of frustration, to deal with due to major health issues. Alyssa Simpson is incredibly professional and takes the time necessary to understand you, your problems, your issues as well as your ultimate goal(s). With me, she then took the time to understand how I was motivated and what was important to me. She then developed a plan tailored to meet my goals built upon my motivations and the held me accountable to living up to my commitments.

The results and that’s what really counts; 27lbs lost over 15 weeks representing over 12% of my body weight. Also a significant reduction in my BMI. And the really good news is that I have developed healthy eating habits, making smart choices and have a better understanding of how to manage my weight and still enjoy life. I couldn’t be happier with the result of working with Alyssa – one of the best decisions I have ever made.

Jack J Tempe AZ


In the first two months I saw my migraines decrease by half. Alyssa has given me the tools to live my life everyday without having to ask myself, Am I getting a migraine?”

I was suffering through about 10-12 migraines every month. I had tried supplements, had worked with a chiropractor and an acupuncturist, and had visited neurologists and physicians.  I never found relief or even a decrease in the frequency of migraines.  I knew my migraines were related to food, but I had no idea which foods and how to eliminate the problem foods without starving myself.

Alyssa was able to have me take a blood test called MRT, and from those results, we worked through a diet process that gave me a clean system for decreasing migraines.  In the first two months I saw my migraines decrease by half.  I also could pinpoint many of my remaining migraines by food that I ate or simply hormonal imbalances.

I would highly recommend Alyssa to others who are suffering from migraines or any diet related issues. Alyssa was a support for me as I learned to eat differently than I ever had before.  She is great at helping make good choices easier.  She engages each patient as an individual and learns what works best for them.  She has given me the tools to live my life everyday without having to ask myself, “Am I getting a migraine?”

Sara B

Rheumatoid Arthritis

Alyssa helped me to find a natural way to improve daily pain in my hands related to rheumatoid arthritis.”

I came to see Alyssa because I was looking for natural ways to manage daily pain in my hands related to rheumatoid arthritis.  Over time the discomfort escalated to extreme pain which resulted in lack of sleep, weight gain, and lack of motivation to participate in daily activities. I had seen a number of doctors, including rheumatologists and acupuncturists. 

Alyssa helped me to create a personalized anti-inflammatory eating plan. By week three and four I started to notice less hand discomfort, and clearer focus. My quality of life has improved tremendously.  I am eager to get up in the morning and start my day.  I now focus on and look forward to fun activities and know that I can do them.

Having lost hope in ever feeling better, I am so happy that I met Alyssa because she has changed my life – naturally, with simple nutrition, her expertise, and her belief that I would feel better.  Thank you Alyssa!

Gina F.

Alyssa Simpson registered dietitian weight loss tips
registered dietitian weight loss tips
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