Here's what one dietitian has to say about the Whole30 diet after trying it out.

From supporters to naysayers, there has been a lot of talk about the Whole30 diet. Here’s what one dietitian has to say about it after trying it out for herself.


First things first: I am not a dieter.

In reality, I’m the farthest thing from it – I’m an eater. I love food. I love exploring with new flavors, cooking up a storm, trying unique restaurants, and embracing different eating experiences. In that same arena, I love healthy foods. I love the idea of fueling my body with nutrient-dense ingredients that will help me power through when I challenge myself to run faster or hike harder than ever before.

I also find immense value in “doing things yourself”. Yes, my beliefs about nutrition are founded in science, but I also believe in listening to your body.

As a registered dietitian, I think it’s important to stay knowledgeable of the latest trends in the nutrition world. So when Whole30 started gaining more traction, I knew I had to give it a whirl for myself to better understand what the hype was about before passing judgment.

So I bought the book and did my homework. I picked a start date, told my family, planned out some meals, made a massive grocery haul and hit the ground running.

Here’s what I learned.

(This article will not help you learn about the details of the Whole30 program. In a nutshell, the focus is no dairy, no legumes, no grains, no alcohol, and no added sugars. It focuses on whole meals, three times per day, cooked at home. If you intend to try Whole30, I recommend purchasing the book and learning all the details there first. As always, consult with a medical professional before going on any restrictive diet.)


I became more diligent about reading nutrition facts labels.

Even as a dietitian, I don’t always read labels every time. I grab a fruit and nut bar based on packaging or taste preference without taking a second glance at the ingredient statement and noticing that ‘honey’ or ‘agave’ is one of the first three ingredients. Spoiler Alert – that’s just a sneaky way to say ‘added sugar’. In particular, I found it especially hard to find brands of dried fruit that did not include added sugar, which I had never noticed prior to starting Whole30.

My sugar cravings went away.

With afternoon sweet tooth attacks that were often only satiated with a piece of dark chocolate or a snack bar, it was safe to say I was craving sugar frequently. Not that there’s anything wrong with satisfying a sweet tooth, but I hadn’t realized how much intentional added sugars I was having everyday.  However, since stopping Whole30 almost two months ago, I haven’t once craved chocolate. This is wildly unheard of for me and probably the biggest takeaway from the entire experience.

I started cooking at home more.

In most cases, those who are on a restrictive diet typically need to make their own food at home. I started making things like egg and veggie scrambles and sweet potato hash for breakfast everyday. It messed with my schedule a bit at first, but once I worked it into my daily routine, it became second nature and  now I genuinely look forward to my new morning routine at home before heading into work.

I slept like a rock.

Most likely a positive side effect of cutting out so much sugar from my diet, I slept like a rock during Whole30. Normally I toss and turn at night but during those 30 days, I got the most restful night sleeps that I’ve had in a very long time.

I lost weight.

Similar to how I am not a dieter, I am also not a constant weigher. I don’t even own a scale, but luckily my roommate does. The program clearly states not to weigh yourself throughout, but to take a pre-Whole30 weight and a post-Whole30 weight. While your health is defined by more than just the number on your scale, my weight did drop in a month.

I felt better.

I typically eat very healthy in general, so to be honest, the Whole30 wasn’t a huge adjustment for me as I’m sure it was for some people. But regardless, at the end of the month, I did feel better than usual. I felt less sluggish, I was feeling confident from dropping a few pounds and my clothes were fitting better, and I felt like my digestion improved and my stomach was rarely upset.

While there were certain noticeable benefits, there were definitely drawbacks.


I got charlie horses.

Usually charlie horses are a result of a fluid-electrolyte imbalance, namely around potassium, calcium, and magnesium.  I drink a ton of water and eat bananas regularly (a source of potassium, which can help prevent muscle cramps). I continued these practices during Whole30, but the overall change in fluid and electrolytes in my body caused my muscles to cramp up more frequently. MAN those muscle cramps are brutal!

I was running on empty.

Literally. I usually wake up at 5am to exercise before work. Often times, I eat a quick snack bar or wafer before running 3-5 miles. I keep it pretty light, just something to get me through a 60-minute workout. On Whole30, all of my usual grab-and-go options were off limits. I opted for a quick few nuts some mornings, but it didn’t work to fuel me as well and even that isn’t technically within the dietary rules of eating a complete meal first thing in the morning. This isn’t a con as much as it was just a general inconvenience for someone who is active.

I had a hard time transitioning off Whole30.

There’s a transition approach included in the book. They have laid out the framework for you clear as day. However, by the end of 30 days, every time I dabbled in an “off-limits” item, I didn’t feel well or I got nervous so I just stuck with the Whole30 approach. It made social events hard and took me quite awhile to figure out my next steps. Plus I work in food daily, so part of my job includes eating foods that may not be part of the program, which was a challenge.

Grains, Dairy, and Legumes have important nutrients.

I’ve always been hesitant of cutting out entire food groups, and this diet cuts out grains, dairy, and legumes. At a basic level, here is my argument about why these foods should remain in your diet:

Grains. Grains provide complex carbohydrates which is your brain’s primary source of energy, as well as dietary fiber to help keep you fuller, longer. Whole30 does allow sweet potatoes which is probably the closest you can get to a grain, so I made an effort to incorporate them into the diet regularly to consistently provide my body with complex carbohydrates.

Dairy. Dairy has important bone-building nutrients like calcium and vitamin D.  These are ESPECIALLY important to women in their 20’s to build bone tissue before they reach peak bone mass at age 30. This helps to prevent osteoporosis down the road, and avoiding dairy could put them at greater risk of osteoporosis. Non-dairy alternatives, like almond milk instead of dairy milk, is often significantly lower in nutrients like protein. One 8-oz glass of almond milk has 1 gram of protein compared to one 8-oz glass of dairy milk that has 8 grams of protein. It’s important to understand that this substitute is not a nutritional parody.

Legumes. Legumes add fiber and protein to your diet and are a really great option for a plant-forward meal. They are especially important for people practicing a vegetarian or vegan lifestyle, as that lifestyle is already limited in protein sources. Plus, many of them offer some of the highest plant-based sources of calcium.

BOTTOM LINE: Be mindful of the science. Understand what you’re doing to your body and what nutrients you are (or aren’t) providing as fuel for your body to function. But also listen to your body and be cognizant of what makes you feel good or bad.

This program was never intended to be sustained as a long-term solution, and for good reason. However, if approached as a 30-day reset, as it was intended, it may help you pay attention to your intentions and practices when it comes to your food habits.


Marissa Thiry, RDN is a Registered Dietitian Nutritionist in Orange County, CA with a passion for health, wellness, and delicious food. With her love of innovating in the kitchen and testing unique flavors from different cultures, Marissa helps others understand that eating should be an experience, not a task. Make a visit to read more from Marissa.