Why can’t you lose weight on a Keto diet?

by | May 22, 2019 | Weight management

What is the Keto diet?

In simplest terms, the Keto diet is a low carbohydrate restricted diet that forces the body to switch from using glucose for energy fuel to burning fat, thus producing ketones.  Many people lose weight on a keto diet but many do not. This article will explore some of the research, safety and risks of trying to lose weight on a Keto Diet.


There are different variations of the Keto diet. Some variations follow less than 50g of carbohydrates (carbs) per day, while some follow less than 20g of net carbs, and others less than 5% of total calories from carbs per day. In comparison, the recommended dietary intake for Canadians aged 19 and over is 45-65% of calories from carbs.


Very low-carbohydrate diets or Keto (ketogenic) diets have been in use since the 1920s as therapy for epilepsy and can, in some cases, altogether remove the need for medication. From the 1960s onward, keto diets have become widely known as one of the most common methods for obesity treatment.


What are ketones?

Nutritional ketosis produces ketone bodies, (acetoacetate, acetone, and beta-hydroxybutyrate) that is measurable in the urine. The production of ketones is the body’s normal adaptation to starvation. Ketones are then picked up by the muscle as fuel. Keeping the body in ketosis is a difficult state to maintain, and often, the benefits are anecdotal.


How do keto diets work?

In general terms, one serving of fruit, bread, vegetables or fruits equals 15g of carbohydrates. The term “net carbohydrates” refers to removing the number of carbohydrates that are not absorbed by the body, such as fibre and sugar alcohols. Because fibre and sugar alcohols are undigestible carbohydrates, some will subtract them from the carbohydrate count and only account for the digestible fuel content of the carb. For example, if a serving size has 15g of total carbohydrates, 3g of fibre and 6g of sugar alcohol, then the net carbohydrate is 15-3-6 for a total of 6g net carbs.


How does your body metabolize glucose and ketones?

We use our body’s carbohydrates (e.g. glucose) that comes from our food for fuel. If there is extra left over the carbs are stored as fat for future use.


With fasting, just as during extended exercise, our bodies flip from using glucose (and storing fat), to using that stored fat and ketones (made from fats) for fuel. Sometimes called the “G-to-K switch,” (glucose-to-ketone) the ability to flip what our bodies use as fuel (between glucose and ketones) is called “metabolic flexibility.”


This metabolic switch can explain some of the health benefits of fasting. When our bodies prefer using fats for fuel, the body starts burning our stored fat. This is why the keto diet helps with obesity, metabolic syndrome, and Type 2 Diabetes. When the body uses fat for energy, this decreases the amount of fat in the body. Reduced fat reduces weight and health benefits from weight loss are felt, such as lower blood pressure and insulin resistance.


This “flipping” of the metabolic “switch” happens after the available glucose, and the stored glucose is depleted. At this point, the fats in our cells start getting released into the blood and are metabolized into ketones. These ketones then go to our fuel cells with “high metabolic activity” – muscle cells and neurons. Since the body is burning fat and using ketones to fuel the muscles, muscle mass is preserved.


Is the Keto diet as good as people claim it to be?

Keto is just another diet to come along and pass into our lives. It is another variance in micromanaging your biochemistry and food intake by limiting your macronutrients.

Macronutrients are the carbohydrates, proteins and fats in our foods that provide fuel. The micronutrients are the vitamins and minerals in our foods.

Your body requires both macronutrients and micronutrients to thrive and survive. When you limit your macronutrients, you risk not getting what your body needs for micronutrients and can end up in a deficiency.


But can I lose weight?

Absolutely. In the short term, you can lose weight following a Keto diet and there is lots of research to support this, but as with all restricted diets, the long term sustainability of this type of diet is challenging and may not be nutritionally safe for you.


I have tried this diet and have not lost any weight

You must remember that you are unique and have a unique genetic makeup and unique life. No two people are the same. As a mom raising identical twin boys, I can tell you that even identical twins with the same genetic makeup are incredibly different in their interests, tastes and attractiveness to foods.


Some reasons that you may not be losing weight include:

  • Consuming too many calories or high caloric snacks

  • Not enough physical activity to burn your caloric intake

  • Chronic stress and lack of sleep

  • An underlying medical condition that is linked to weight management issues such as Polycystic Ovarian Syndrome (PCOS), Cushing’s Syndrome, Hypothyroidism, Depression and Hyperinsulinemia (high insulin levels)

  • Overeating protein can also interfere with ketosis


The safety of the Keto diet

Research studies have shown that low-calorie keto diets that are part of short-term interventional weight loss programs are safe. Weight loss and improvement in glycemic control for Type 2 diabetes have been noted as compared to standard diabetic diet guidelines.


Low-carbohydrate diets are beneficial for the improvement of weight, triglyceride levels, and HDL  (bad cholesterol), in healthy adults and are easily adhered to over 12-weeks. Longer term adherence and the different degrees of carbohydrate restriction is currently unknown.


Keto risks:

  • High in saturated fat, which is linked to heart disease and increase in LDL “bad” cholesterol

  • Nutrient deficiency of micronutrients if you don’t eat a variety of foods

  • Liver problems because there is too much fat to metabolize

  • Kidney problems due to metabolized protein

  • Constipation due to low in fibrous foods

  • Fuzzy thinking and mood swings. The brain needs healthy carbohydrates to function


If you have a medical condition or take medication, you want to talk to your doctor or a Registered Dietitian such as myself, before starting any new eating regime or diet. The change in body chemistry can affect your medication dosage and effectiveness.


To learn more about what foods you should be eating to maintain a healthy lifestyle, book a free 15-minute consultation. I work with individuals, couples and families who are looking for ways to integrate healthy and nutritional balanced meals that are supportive of their dietary restrictions, in a way that is easy and fun. Book a time that works for your schedule by clicking here.

Get in touch with Keren and book a free 15-minute discovery call today!

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