Simple fitness that works, from pregnancy to seasoned athlete.

Diets Decoded: Mediterranean, Paleo, Ketogenic, and Whole30

by Stephanie Margolis, R.D.
Updated January 3, 2023

How can we pull the greatest benefits from some of these diets and still enjoy eating? A lot of these diets have the same principles and I will show you how they can work best for you. Note: The information listed below is not specific to breastfeeding or pregnant moms. For more nutrition guidance visit our pregnancy and breastfeeding nutrition articles.

Your friend shows up to a playdate, slightly grumpy, but looking a little trimmer so you ask what she’s doing. Next thing you know you’re knee-deep in the intricacies of the keto-Whole30-paleo plan she’s following for the month. It is very attractive to hear, and you may be wondering if one of these diets is right for you.

How I Design Meal Plans as a Dietitian

In my practice as a dietitian, I’ve found different approaches click for different people — there is not one perfect approach. When designing a balanced meal plan for women wanting to lose weight and eat more wholesome foods, I aim for about 30 – 50% carbs each day. Almost every gram of carb comes from whole grains, fruits, and vegetables — so even if you aren’t following a meal plan, you can focus on increasing these three things.

Additionally, I restrict refined sugars, only allowing those sugars that are found naturally in foods such as fruit (fructose) and milk (lactose). To balance the good carbs, I also average 100 – 112 grams of protein each day — approximately 30% of a diet plan. This leaves the rest of the “plate” for good fats (think avocado, healthy oils, nuts, and seeds). You can find this meal plan alongside the Moms Into Fitness workouts.

Like many things, you want to consider what is healthy AND sustainable for you as a mom. When it comes to some of the most popular diets on the market today there are a few things you should know and precautions you should take before diving in.

Before You Start a Diet

General Pros: There are some diets that have shown positive outcomes for certain clients. If you have a food allergy or sensitivity, you may find relief with some of the options out there. For some, a short-term, strict diet can help reset the mind, but there are less intense ways to get this same result. These less intense ways can also offer a lifestyle solution.

General Cons: Most diets are not sustainable over the long term. Most will deliver results in the short term because of their incredible restrictions; however, when the diet/challenge/cleanse is over the weight returns. This leads to yo-yo dieting and a lot of frustration.  While most diets reset your system, you have to learn how to sustain some of the principles learned while on the diet, so the yo-yo does not occur.

General Bottom Line: Whole foods, reducing added sugars, and incorporating, as many fruits and veggies as you can is always a good move. Severely restricting caloric intake, having a long list of rules related to food, or cutting out an entire food group (ahem… carbs!) may make for some short-term gains but is very likely to fail you in the long run (and leave you hangry).

All that being said, let’s take a closer look at some of the popular trends we see in the diet world.

Mediterranean Diet

The What: The Mediterranean Diet has been the #1 ranked diet in many rankings for years. This diet is rich in fruits, vegetables, olive oil, and fish, with an emphasis on plant-based meals. In this meal pattern you are limiting saturated fats, added sugars, and sodium. All which are correlated to poor health outcomes.

The How: In the Mediterranean Diet you fill your plate with a wide range of foods to include fruits, whole grains, nuts, legumes, olive oil, herbs, and spices. You are encouraged to eat seafood at least twice per week. Poultry, eggs, cheese, and yogurt are permitted but you’re encouraged to enjoy them in moderation. Red meats and sugary foods are deemed “treats” but an occasional glass of red wine gets a thumbs up.

The Weight Loss: While many lose weight on the Mediterranean Diet the research and support for the pattern speaks to the positive health outcomes. In many studies, those who follow the diet have longer lifespans, reports higher quality of life, and are less likely to suffer from chronic diseases. It is specifically known for it’s heart-healthy outcomes and positive impact for those with Type 2 diabetes. However, there is early evidence it may help prevent cognitive decline and dementia

The Risks: This diet has virtually no risks. The only trouble I find for clients is that the meal planning and prep can be laborious because you are eating fresh foods which require work. There are also fewer “rules” that you find in some diets discussed later.

The Bottom Line: Easily the best diet to follow if you are looking to lose or maintain your weight while also boosting your health. The Mediterranean Diet encompasses a balanced way of eating that can be managed for a lifetime.

Ketogenic (Keto) Diet

The What: The ketogenic diet has been around for a long time, primarily used in the treatment of those suffering from epilepsy. More recently ketogenic diets have shown promise in treating many conditions including type 2 diabetes, polycystic ovary syndrome, and neurological diseases. (1)

The How: The ketogenic diet does not focus on caloric intake, instead it focuses on reducing glucose from carbohydrates (typically to 50g per day or less). (1) At the same time the diet aims to increase protein and fat. Carbs are the body’s first fuel, so after a few days of restricted carbs, the body switches to burning fat. Our bodies cannot make glucose and have about 24 hours’ worth stored in muscle tissues, etc.  Once that glucose is no longer available, the body uses fat as its source of fuel instead.  As a result, the body also produces ketones that exit the body through urine (hence the name, keto diet).

The Weight Loss: We see a strong correlation between this diet and weight loss. This happens through feeling less hungry (more fat and protein will do that to ya!) and the body is using more energy to digest and use the fuel you are providing.

The Risks: Following a true ketogenic diet does have its downfalls. When consuming high amounts of protein there is always the risk of kidney damage due to the high levels of nitrogen excretion and the toll it takes on the body’s filtration system. While the keto diet shows promise for individuals suffering from certain diseases, there is no evidence about its absolute effectiveness for those without those conditions and there are some doubts about the diet’s safety.

The Bottom Line: Proceed with caution. Ketosis is not harmful to healthy individuals; however, you want to monitor your healthy beyond just weight loss. If you feel excessively fatigued or otherwise uncomfortable you should stop the diet. Even with a good amount of clinical evidence to support its effectiveness, eating a diet plan that is purely keto can be very restrictive and repetitive, which can be very difficult long term and with a family.


The What: The Whole30 diet is probably most known for how incredibly strict is it — swearing off most foods and leading you to find a lot of substitutes. While many take on this diet for weight loss, another reason some turn to this is to identify a food allergy or sensitivity. This approach is what we, in the dietetics field, may also call an elimination diet. In an elimination diet, you strip the diet to its bare bones, allow the gut to “rest,” then start reintroducing foods in a strategic way. During this process, you are searching for GI distress/or lack thereof, to pinpoint the food trigger. While there is science behind several of the claims made by the diet, not all the “no” foods have the facts to back up the reason to eliminate them.

The How: In the beginning of the 30 days you cut out dairy, sugar, legumes, grains, and alcohol. You stick with mainly whole foods and you get through the month. At the end of the 30 days there is a reintroduction phase where you add foods back in slowly, with the idea that if you do have a food sensitivity, once that food has been added back in, you will notice some symptoms and be able to red flag it.

The Weight Loss: Most people lose weight on Whole 30 because it is restrictive (e.g., if you get gluten on your food — even accidentally — you are supposed to start the entire 30 days over). Even though you are not counting calories, or even really controlling portions, you are likely eating less. One common complaint is also that it is boring and becomes difficult to enjoy a variety of foods, which could also lead to weight loss. On the positive side, you could see weight loss if you have a true food sensitivity because your gut is no longer as bloated and you have shed a few pounds by finding foods that work for you. Some positive things in the Whole 30 diet is that they really do promote planning your meals and tell you firmly that cupcakes are an absolute “no” and sometimes it’s good to have those clear parameters.

The Risks: Ultra-restrictive diets usually backfire. While there are Whole 30 success stories there are many success-then-back-to-status-quo stories too. Some regain any weight lost during the 30 days and some even gain more. With any dietetic change you must consider if it is something you can do long term using the principles learned while doing the 30 day plan.

The Bottom Line: Proceed with caution and prepare to be completely consumed by this diet. Following such a strict regimen is very time intensive, and because many of the foods are fresh and specialized, there are many trips to the grocery store involved to maintain this diet. Again, making this a lifestyle is difficult because of the limited food list. If you are concerned about a food allergy or sensitivity I would strongly urge you to talk to a health care professional before taking it in to your own hands with a restrictive diet.

If you’re curious about elimination diets, check out this article for my approach.


The What: Paleo diet plans have been around for a very long time but have a recent resurgence with the CrossFit community. You will probably hear the term “caveman” associated with this diet with the idea that if a caveman wouldn’t eat it, neither will you.

The How: Throughout this diet you are limiting many foods, especially processed foods. You also cannot have dairy, refined sugar, potatoes, salt, or refined oils. You can have meat, produce, nuts, seeds, and non-refined oils. This is touted as being a lifestyle, so unlike Whole30, the timeline is not defined.

The Weight Loss: As with many other extreme diets, you will lose weight. The issue becomes when you completely cut out food groups your body can become malnourished — unless you are extra diligent about tracking your intake, macronutrients, and micronutrients. Also, the question of “can I do this forever?” arises. Another trend I have seen with this specific diet is all the paleo foods that have hit the marketplace. While it may make it easier to eat this way, you must wonder if they are truly compliant to the diet, and is it worth the higher price tag the specialty food usually comes with. Finally, when I have worked with individuals on this diet I typically see them lose weight due to a calorie restriction — they are cutting the pasta out and not replacing it with anything. It is hard to know if they are shedding pounds from the composition of the diet or the reduced calories.

The Risks: Some individuals experience GI distress or other health concerns when consistently eating a diet high in protein and fats. There is also the risk of fatigue due to the low carb intake, especially if you are not adding extra calories and carbohydrates through fruits and vegetables.

The Bottom Line: The part of the diet that emphasizes whole foods, lean meats, and less processed foods is fantastic. The concerning parts are those that involve a very restrictive diet that requires a large amount of meal planning and food prep that can be unsustainable in the long term.