how does the ketogenic diet work?
The goal of ketogenic diets is to send the body into a state of “ketosis” by using a very strict low-carb diet. This general term can include diets such as the Atkins diet, the Dukan diet, and LCHF (low-carbohydrate, high-fat) diets such as the Banting diet, although the proportions of fat, protein, and carbohydrates and other specific characteristics of each diet (eg, ‘) may vary.
what is ketosis?
Under normal circumstances, our bodies use glucose from carbohydrate foods for energy. in the absence of glucose, a process called ketosis occurs. this is a state in which the body burns fat instead of carbohydrates as its main source of fuel. When we don’t eat carbohydrates, the liver breaks down fat stores for energy. this energy is in the form of (and also creates) molecules called “ketones”.
how are ketogenic diets used in a medical setting?
Ketogenic diets were originally developed to treat epilepsy in children, as it appears to reduce seizure frequency. It should be noted that the use of the diet in this context should not be attempted without the supervision of a specialized physician. From these medical origins, the diet was picked up by the mainstream media and marketed as a weight loss regimen; It is in this context that we will discuss diet for the purpose of this article.
what foods are allowed on a ketogenic diet?
Foods generally allowed include meats, fish, oils, nuts and high-fat dairy products, such as cheese, and low-carbohydrate vegetables, such as green leafy vegetables.
Unsurprisingly, lowering your carb levels means cutting out bread, pasta, rice, and most conventional baked goods. however, achieving such low carb levels also means skipping legumes, tubers, most fruits, and starchy vegetables like potatoes.
we asked nutritional therapist kerry torrens for her opinion…
is it safe?
This eating plan certainly contradicts most people’s understanding of a healthy, balanced diet that typically promotes the consumption of protein, fat, and carbohydrates. From an evolutionary perspective, ketosis is a normal adaptive response that allowed humans to endure periods of famine throughout history. Today, this natural physiological mechanism has been exploited by a number of low-carbohydrate dietary regimens. following such a diet means that you will replace carbohydrates with foods rich in fat and protein, and if followed for a long period of time, this can have unfavorable consequences for some people. An intake of high-fat foods is likely to increase your intake of saturated fat, which current UK government guidelines recommend we limit to 30g for men and 20g for women. High levels of dietary protein are thought to be a problem if you have an underlying kidney condition. however, most ketogenic diets provide moderate rather than high levels of protein.
is it effective for weight loss and is it sustainable?
Ketogenic diets generally cause weight loss and may improve insulin sensitivity in patients with diabetes. in fact, when compared to a low-fat diet, a ketogenic diet appears to achieve greater long-term reductions in body weight. however, long-term success depends on your ability to adjust your eating habits once you begin to introduce a more balanced and healthy approach to eating.
How are the different versions of ketogenic diets different?
The standard ketogenic diet (skd) appears to be the most researched, particularly with regard to its ability to help people lose weight and control blood sugar. typically comprises 70-75% fat, 20% protein, and 5-10% carbohydrates. When following a ketogenic diet, be sure to include plenty of non-starchy vegetables like kale and spinach, which are very low in carbs.
what should I do before starting a ketogenic diet?
If you are interested in adopting this type of diet, you should consult your GP to confirm if it is appropriate and safe to do so. Before starting the diet, focus on foods that support the liver, such as garlic and onions, and try to reduce your intake of sugar, caffeine, and alcohol.
Who should be more careful when following a ketogenic diet?
Diabetics, especially type 1 diabetics, are at risk of complications if they try to follow a ketogenic diet. For this reason, diabetics and anyone with blood sugar control problems should discuss the potential implications with their GP and health care team before embarking on such a regimen. Similarly, anyone with kidney disease or a family history of it should see their GP.
what are the long-term effects of ketogenic diets?
Symptoms associated with ketosis are usually temporary and may be related to dehydration. These can include headache, dry mouth, bad breath, fatigue, and nausea. however, it is worth noting that because the diet restricts carbohydrates, it is generally low in dietary fiber, which can negatively impact gut health, including the presence of gut-friendly bacteria. In this case, be sure to eat plenty of gut-friendly foods, such as green leafy vegetables, fermented vegetables, and certain fats like butter, which provide butyric acid, a short-chain fatty acid that helps your gut.
Please note: If you’re considering trying any type of diet, check with your GP first to make sure it’s safe to do so.
now read…
how to eat a balanced dietsix things to consider before going on a dietall of our popular diet guides
This article was last updated on January 4, 2022.
kerry torrens, a registered nutritional therapist, is a contributing author to several nutrition and cooking publications, including bbc good food. Kerry is a Fellow of the Royal Society of Medicine, Natural and Complementary Health Council (CNHC), British Association for Applied Nutrition and Nutritional Therapy (BANT).
All health content on bbcgoodfood.com is provided for general information only and should not be treated as a substitute for the medical advice of your own physician or any other healthcare professional. If you have any concerns about your general health, you should contact your local health care provider. see the terms and conditions of our website for more information.
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