A Dietitian’s Review: The Keto Diet (or a Very Low Carb Diet)

Blog, Food

By Melinda Maryniuk, MEd, RD, CDCES

We review several different eating approaches in our “Dietitian’s Review” series with the goal of helping people who are looking to evolve their eating style towards better health. It’s important to emphasize that “going on a diet” is very rarely associated with long-term success with weight. We provide these reviews for anyone who wants to improve their health and is looking for an eating approach that will best fit their lifestyle and preferences.


Meal plans that are very low in carbohydrates are grabbing attention for both weight loss and also blood sugar control (among people with type 2 diabetes.) The “keto” in keto diet stands for ketogenic. It is a diet very low in carbs and high in protein and fat. When the body does not get enough glucose from carbs, it will start burning fat. In the process of burning fat, a by-product is released called “ketones”. This low level of ketones (referred to as “nutritional ketosis”) is not dangerous and not to be confused with diabetic ketoacidosis, a potentially dangerous condition related to very high blood sugar levels in people with type 1 diabetes.   The low level of ketones present in nutritional ketosis blunts the appetite, and in addition, when you eat mostly fat and protein, you feel full. The keto diet usually allows only 50 grams or less of carbs per day.

What do I eat?

The meal plan consists primarily of carb-free sources of fat and protein including: meat, seafood, eggs, oils, butter, nuts, seeds and cheese. Because the amount of carbohydrates is so limited, only certain low-carb fruits and veggies are recommended such as asparagus, cauliflower, dark green leafy veggies, berries, lemons and avocados. All grains are avoided. If flour is used, it should be nut-based such as almond flour or coconut flour which is lower in carbs.  Even nuts that have small amounts of carb (such as cashews or pistachios) are avoided. No alcohol.  One can find many food lists online for more detail.

Is it effective?

There are a number of published research studies showing that the diet is helpful in both lowering weight and lowering blood glucose levels (in people with diabetes).  However, these studies often have a larger drop-out rate (meaning most people can’t stick with a diet like this for too long).  No research has been carried out for more than a year.  If this is something you want to try for a few months, there may be no harm, but it’s best to talk with your doctor and dietitian, especially if you have diabetes, as you may need some changes in your medications to reduce risk of hypoglycemia or other possible problems.

What are some pros and cons?

Pros: Very popular. You will likely eat less and lose a little weight – short term.

Cons: Ketones can lead to a “fruity smelling” breath (not in a good way) and some other side effects including headache or “keto flu” symptoms. This approach does not form healthy long term eating habits. It can be expensive and time-consuming to buy all the meat and special foods. Finally, there is no research regarding the impact of omitting important food groups over time, not getting adequate fiber, and other nutrients such as calcium.

Note for people with diabetes:  

Both the American and Canadian Diabetes Association recognize that very low carb diets have demonstrated some success, especially for people with type 2 diabetes.  There is limited data for type 1 and for that reason, they are not recommended.  If you have type 2 diabetes and want to consider this type of meal plan, talk with your doctor or healthcare provider about the safest way to approach it.  A diet very low in carbs can increase the risk for hypoglycemia, and therefore diabetes medicines such as insulin and sulfonylureas may need to be adjusted.  This meal plan approach is not recommended for women who are pregnant/lactating, those who struggle with disordered eating patterns, take a diabetes medicine called an SGLT-2 inhibitor or have kidney disease.  

How do I learn more?

A ketogenic diet for beginners   www.dietdoctor.com/low-carb/keto

It is strongly recommended if you choose to try a  very low carb or Keto plan to talk with your doctor and dietitian. 

What do I buy at the grocery store?

Note: There are many approaches to weight loss that can be successful for people.  My Weight– What to Know does not recommend a particular diet, but is happy to share facts about a variety of approaches. As with all meal planning approaches, regular exercise is recommended.

Eating a healthy diet and being active are both really important for being healthy, but for many people diet and exercise alone aren’t enough to help them reach their weight-loss goals. If this sounds familiar, read this fascinating article about what to do when diet and exercise aren’t getting you to where you want to be.

UPDATE: A recent study from the NIH suggests that a diet high in ultra-processed foods led to overeating and weight gain. Watch a Facebook Live episode that covers what to know about ultra-processed foods here:

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