As a public health nutritionist, I like to keep track of current trends in the dieting world and wow 2020 was the year of the keto diet! On average there are a million internet searches a month for the phrase “keto diet for weight loss” and Youtube health and fitness world is full of people sharing their success stories of dropping 10lbs in a week, curing diabetes and overcoming binge eating on a keto diet. You might be wondering whether you should try the keto diet for weight loss. In this article I want to explain a bit about the keto diet, how it works for weight loss and some of the potential risks so that you can make your own mind up.
For anyone not familiar, a keto diet is a high fat, very low carbohydrate diet meaning that grains, potatoes, beans, most fruits and some legumes are off limits. The maximum recommended carbohydrate intake is usually between 20g and 50g per day, sometimes less in the beginning. If you ate this amount of carbohydrates from bread and pasta it wouldn’t add up to much! So generally these carbohydrates come from non-starchy vegetables such as leafy greens, cruciferous veggies, peppers and courgettes as shown in the plates below by the Diet Doctor.
The majority of your energy intake on a keto diet is from fat, usually 75% of calories come from fat, 20% from protein and 5% from carbohydrates. Fat sources are often animal products such as meat, eggs, lard, fish and dairy but there is also the magical unicorn “vegan keto” which only includes plant-based sources such as oils, nuts and seeds. The difference between the Atkins diet and the keto diet is that Atkins diet focuses on the low carb aspect and doesn’t set any limits for protein, whereas keto emphasizes the importance of consuming only a moderate amount of protein. This means that you can’t just eat bacon and cheese all day on the keto diet as they have too much protein!
How does the keto diet for weight loss work?
The keto diet for weight loss works by putting you into the metabolic state of ketosis. Your body has this back-up mechanism for generating energy when carbohydrates are unavailable, for example during periods of fasting or famine, extended intense exercise or a low-carbohydrate diet. In ketosis, your liver produces ketone bodies from fatty acids which are then transported to your cells to be used in place of glucose for energy. The theory is that adapting your body to run on fat rather than carbohydrates allows your body to turn more easily to it’s own fat stores for energy rather than sending out signals for you to consume more carbohydrates every time your blood sugar drops.
Once you are off the blood sugar rollercoaster, you no longer experience the dips which cause you to experience hunger and cravings. Those who follow the keto diet claim that their hunger levels are significantly reduced and they can go much longer periods of time without feeling hungry. On the keto diet, you have the majority of your calorie intake coming from fat. Even though fat is more energy dense having more than twice the calories per gram compared to carbohydrates and proteins, it also which triggers release of satiety hormones which make you feel full. This helps some people to feel satisfied on much less food than they usually would, especially when fats are combined with low calorie vegetables which provide fiber and water.
By excluding carbohydrates, the keto diet for weight loss also completely cuts out many energy dense processed foods such as chocolate, soda, sweets, cakes and other baked goods. For some people with more black and white thinking, eliminating these foods altogether is easier than trying to eat them in moderation and it makes decisions about what to eat more simple. Over time on the keto diet for weight loss, your taste buds can adjust so that you no longer have cravings for these foods. This is great if you are trying to beat a sugar addiction! Of course there are energy dense snack foods on the keto diet too, especially nuts and seeds, but generally these are harder to over eat because they are so filling.
What are the downsides of the keto diet for weight loss?
Even though the keto diet for weight loss works short term, I’m not convinced that it is sustainable long term.
It’s not easy
Firstly, it’s complicated! Some people test their urine using ketone-strips or test their blood ketone level to check whether they are in ketosis which can be pretty invasive. At least in the beginning you have to learn the carbohydrate content of different foods and have some way of tracking what you eat to make sure that you are below the recommended 20-50g of carbohydrates per day. I’m sure that over time this gets easier, especially if you eat similar foods day to day, but it still needs some attention and certainly isn’t for everyone. The world isn’t exactly keto-friendly either and finding options to eat when out socialising with friends and at family or work events could be a challenge.
Food choices are limited
Even if you decide that the complexity is worth it, the risk with any diet that cuts out whole food groups is that your food choices are limited which puts you at a greater risk for nutritional deficiencies. Of course, a well-planned keto diet which includes a variety of vegetables, animal and plant fats can be nutritionally adequate but I’m not sure that every person following this diet is going to do their research and pay enough attention to their diet to make sure they are getting everything they need. Short term in a healthy person this is unlikely to be a problem but when someone attempts the keto diet after a long line of other failed diets, they may already have depleted nutrient stores and could run into problems down the line. Restrictive diets also put you at a greater risk for binge eating and rebound weight gain.
Risk of under-eating
Another risk of the keto diet for weight loss is that your appetite might be reduced to the point where your don’t eat enough. You might laugh at this one, especially if you think your problem is eating too much, but when you are removing so many types of foods from your diet it can be easy to accidentally under eat. the problem with extremely calorie restricted diets is that can be very stressful for your body. I wrote above why calorie restricted diets don’t work in a previous post so you can check that out for more information but in short, when your body perceives a large energy deficit, it starts to freak out and tries anything it can to reduce your energy output and maintain balance. This is commonly known as starvation mode and can lead to low energy levels, fatigue, slow growth and repair, and hormonal issues.
Increased stress hormones
On the other hand, many people report feeling high energy when they start out on the keto diet. This might seem like a positive but it can be a sign that your body is releasing stress hormones cortisol and adrenaline as it struggles to adjust to the extreme change in diet. Cortisol is normally released by your body during low blood sugar events to trigger release of stored glucose from your muscles into your blood stream and this can be more intense as your body adapts to ketosis. Reports of hair loss, sleep issues and menstrual disturbance in women who attempt the keto diet can be because it is just too stressful for the body. Again, a generally healthy person may be able to handle this adjustment period but someone who is already under a lot of pressure and stress might want to think twice about whether the keto diet is for them.
Risk of complications
Finally, there is the risk of medical complications with the keto diet. Removing carbohydrates affects the water and electrolyte balance in your body and can lead to dehydration, low blood pressure and kidney problems. The “keto-flu” is common as the body transitions into ketosis and can cause headaches, dizziness, nausea, bad breath and low energy. The keto diet was originally developed to cure epilepsy and was carried out under medical supervision. It is now being widely promoted as a weight loss diet but the long term impacts of the diet on the body are not fully understood. If you decide to try out the keto diet, you should know you are putting your body in an extreme state and effectively conducting a science experiment on yourself!
So should I try the keto diet for weight loss? And how can I reduce the risks?
It’s not for me to say whether you should try the keto diet for weight loss or not. It isn’t something I would try myself or recommend to my health coaching clients but there are definitely people who have had success with it. I would always ask the question of whether you need to put your body through such extremes or whether there is an easier way. But with that being said, if you do decide to try it out I’d suggest the following to reduce the risk and make the transition smoother:
- Always speak to your doctor before you start out. Check that you have no pre-existing medical conditions or nutrient deficiencies that could be made worse by the keto diet.
- Do your research. Don’t just dive into the keto diet but take some time to research what to eat to get the nutrients you need as well as other precautions to take or supplements you might need.
- Transition slowly. Rather than going from a standard omnivore diet straight into keto, try gradually decreasing your carb intake over time to give your body chance to adjust.
- Stay aware of your physical and mental health. If you feel like you are suffering in any way, don’t be afraid to “fail” the diet. The keto diet is definitely not for everyone and it is ok if it doesn’t work for you.
Over to you..
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