Obesity remains a serious and relevant public health concern throughout the world, despite related countermeasures being well understood (i.e., mainly physical activity and an adjusted diet). Among different nutritional approaches, there is a growing interest in ketogenic diets (KD) to manipulate body mass (BM) and to enhance fat mass loss. This article delves into the ketogenic diet (KD), examining its physiological basis, effects on body mass reduction, and body composition improvements. We will also explore the practical aspects of incorporating KD into daily life, particularly with readily available cookbooks like "30-Minute Ketogenic Cooking."
Understanding the Ketogenic Diet
A KD reduces the daily amount of carbohydrate intake drastically. Based on the previously mentioned classifications, a KD is a very LCD, high in fat, with variation in protein intake but may be classified as moderate or high. This macronutrient distribution leads to an increase in the production of ketone bodies (KB) and consequently to physiological ketosis (i.e. This results in increased fatty acid utilisation, leading to an increase in blood ketone bodies (acetoacetate, 3-β-hydroxybutyrate and acetone) and therefore metabolic ketosis. For many years, nutritional intervention studies have focused on reducing dietary fat with little or conflicting positive results over the long term. Moreover, current nutritional guidelines for athletes propose carbohydrate-based diets to augment muscular adaptations.
The literature outlines that carbohydrate-restricted diets (LCD and KD) are increasingly used to manage various health conditions, including neurological disorders, obesity, dyslipidaemia, hypertension, diabetes, the metabolic syndrome and various cancers. As a result, carbohydrate-restricted diets have gained substantial popularity.
Historical Context
The KD has been studied periodically for more than 100 years. However, over the past 30 years, a growing body of research has suggested that a link exists between the process of KD adaptation and a broad range of health benefits. Dr. Russel Wilder first used this type of diet to treat epilepsy in 1921 and described the term ‘ketogenic diet.’ Because of Wilder’s observed beneficial results, the KD assumed a place in medical nutrition as a therapeutic diet for paediatric epilepsy and was widely used until its popularity declined as antiepileptic agents were introduced.
Types of Ketogenic Diets
There are several versions of the KD. However, we considered only the following types of KD, which are more readily available in the scientific literature. Historically, classic KD was proposed by Dr. Wilder in a series of patients with epilepsy in the Mayo Clinic. Modified Atkins diet limits the amount of carbohydrates consumed to 10-20 g/d (10 g for children and 20 g for adults), which was introduced as an alternative to the classic KD in 2003. Modified Atkins diet does not restrict energy content, fluid or protein and allows a greater portion of carbohydrate and protein intake than the classic KD (e.g. Very low-energy ketogenic diet is a nutritional intervention that mimics fasting through a noticeable restriction of daily carbohydrate intake, usually lower than 30 g/d (≃13 % of daily energy intake). The Mediterranean version of the KD has been widely studied in previous years.
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Food Selection on a Ketogenic Diet
Food selection is a major consideration for individuals undergoing a KD. High-carbohydrate food consumption is strictly controlled and limited during a KD; however, it is not a ‘no carbohydrate diet.’ Meal preparation often incorporates unprocessed foods consisting primarily of cruciferous and leafy green vegetables, raw nuts and seeds, eggs, fish, unprocessed animal meats, high-fat dairy products and natural plant oils, including fats, avocados, coconuts and olives. In addition to the KD foods listed in Table 2, ketogenic eating plans frequently promote meals such as omelettes, salads and animal protein such as steak, salmon or chicken with vegetables.
The Science Behind Ketosis
Glucose is a vital fuel substrate for fat oxidation and central nervous system activity. Its role is particularly crucial in cell energy production because it is a precursor of oxaloacetate, a required substrate for the Krebs cycle. The Krebs cycle also gives its intermediates in other biosynthetic processes. This intermediate pool replenishment process is called anaplerosis. The endogenous production of glucose in the body, particularly in the liver, from lactate, glycerol and the amino acids alanine and glutamine is known as gluconeogenesis.
In humans and most other mammals, acetyl-CoA formed in the liver during the oxidation of fatty acids can either enter the Krebs cycle or undergo conversion to KB. During a KD, the concentrations of glucose drop and the glucose reserve is not enough to guarantee oxaloacetate production for anaplerotic function. In this condition, the organism requires an alternative source of energy, which is found in the form of KB. The three KB are acetoacetate (AcAc), beta-hydroxybutyrate (BHB) and acetone. The production of KB occurs in the liver from two acetyl-CoA molecules through a metabolic process called ketogenesis.
When oxaloacetate is not available due to a shortage of glucose, acetyl-CoA accumulates and spontaneously diverts into the formation of AcAc, and then BHB. Two molecules of acetyl-CoA catalysed by thiolase and produce acetoacetyl-CoA. The acetoacetyl-CoA then condenses with acetyl-CoA to form beta-hydroxy-beta-methylglutaryl-CoA cleaved to free AcAc and acetyl-CoA. The AcAc is reversibly reduced by BHB dehydrogenase, a mitochondrial enzyme, to BHB. AcAc can also form acetone. KB are then released into the bloodstream and can be absorbed by other tissues to be reconverted to acetyl-CoA and therefore provide a fuel substrate for the Krebs cycle. This process is of importance for the brain due to its incapability to utilise directly NEFA as a source of energy.
NEFA are unable to cross the blood-brain barrier. For this reason, the brain ordinarily uses glucose and, in low glucose conditions, becomes dependent upon KB. The rapid rise of circulating KB leads to ketonaemia and ketonuria.
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Physiological Effects of Ketosis
Previously, interest in the KD focused on its role in epilepsy and expanded upon our knowledge of underlying biochemical mechanisms in both normal and pathologic brain function. The KD acts by inducing a state of physiological ketosis, which has been linked metabolically to some anticonvulsant properties via reduced glucose, elevated fatty acid concentrations and enhanced bioenergetics reserves. Besides, regarding its effects on brain function and anticonvulsant effects, KD affect numerous other physiological and biochemical processes. Dramatically reducing carbohydrate intake and thus decrements of insulin and leptin and increased glucagon concentrations also play a role in regulating protein and TAG balance, which results in reduced lipogenesis while increasing lipolysis. Interestingly, fuel sources in a KD are fatty acids (70 % of energetic requirements from dietary fat and lipolysis of adipose tissue pools), KB (20 % of energetic requirements from lipolysis and ketogenesis adipose stores) and glucose (10 % of energy requirements from gluconeogenesis). Numerous factors such as BMR, BMI and BFP may be improved through ketogenesis.
Keto-Adaptation
The body begins using primarily ketones as energy fuel after a few days or weeks from the beginning of the diet. This phenomenon is called ‘keto-adaptation’ and can vary between individuals. The mechanisms that promote keto-adaptation are still poorly understood; however, some authors have proposed the hypothesis that mitochondrial biogenesis and decrements of mitochondrial damage in oxidative tissues (such as brain and muscle) may be one of the possible mechanisms. For example, studies on muscle tissue showed that a KD could contribute to mitochondrial biogenesis and reduce mitochondrial autophagy, contributing to a rich mitochondrial reservoir in the muscle tissue, enhancing exercise performance and athletic’ well-being.
Benefits and Risks of Ketogenic Diets
During recent years, KD have been commonly considered a beneficial strategy to treat numerous diseases and BM and FM control. In fact, many studies suggest that they could be more efficient than low-fat diets (LFD). Regarding predisposing factors, numerous findings have shown that baseline insulin dynamics or genotype patterns could play an important role in the success of a LFD v. a KD on BM loss. For instance, individuals with greater insulin resistance might be more successful following KD due to the reduced requirement on insulin to clear a lower quantity of dietary carbohydrates delivered in the blood circulation.
Potential Complications
KD’ serious complications appear to be rare; however, pre-existing conditions such as porphyria, pyruvate carboxylase deficiency, defects in fatty acids oxidation and mitochondrial disorders have reportedly worsened over time. Dehydration is typically characterised by dry mouth, headache, dizziness/orthostatic hypotension and electrolyte abnormalities (such as hyponatraemia and hypomagnesaemia), and visual disturbance is the most common short-term side effect.
Ketogenic Diets for Weight Management
Obesity remains a significant public health concern throughout the world. According to the latest data from the WHO, the prevalence of obesity is increasing, with 13 % of adults worldwide classified as obese and 39 % classified as overweight. Associated co-morbidities such as CVD, type 2 diabetes mellitus and various types of cancers are expected to rise dramatically in conjunction with the global obesity epidemic. While increasing efforts continue to combat this disease, body mass (BM) loss strategies remain a complex and challenging dilemma for health care practitioners and individuals with obesity. Various dietary strategies have long been proposed for BM loss. One popular dietary strategy is classifying a diet based on macronutrient intake, including fat, protein and carbohydrate. Nowadays, a low-carbohydrate approach is a popular strategy for decreasing BM and fat mass (FM).
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KD may act as a viable strategy for BM loss, particularly in the short term; however, BM loss may be accompanied by a loss of lean mass. Due to the importance of BM and the relevance of properly maintaining body composition, the efficacy of KD on BM and body composition is an intriguing area of experimental research. A focus on body composition during BM loss is critical to monitor changes in FM while maintaining or even improving lean mass. A KD-derived BM loss programme is acknowledged as an efficient intervention within the first few weeks of implementation. Nevertheless, the evidence for body composition alterations during a KD is inconclusive.
In summary, based on the current evidence, KD are an efficient method to reduce BM and body fat in both individuals with obesity and athletes. However, these positive impacts are mainly because of the appetite suppressive effects of KD, which can decrease daily energy intake. Therefore, KD do not have any superior benefits to non-KD in BM and body fat loss in individuals with obesity and athletic populations in an isoenergetic situation. In sedentary individuals with obesity, it seems that fat-free mass (FFM) changes appear to be as great, if not greater, than decreases following a low-fat diet. In terms of lean mass, it seems that following a KD can cause FFM loss in resistance-trained individuals.
Incorporating the Ketogenic Diet into Daily Life: 30-Minute Keto Solutions
Kyndra Holley knows that one of the biggest challenges people face when transitioning to and sticking with a whole foods-based ketogenic lifestyle is carving out time to cook day after day-especially on busy weeknights when life is pulling you in a million directions. Preparing healthy low-carb meals from scratch, without relying on prepackaged convenience foods, can leave you feeling like you spent hours in the kitchen, all for a meal that’s just a memory within a few minutes’ time.
Being no stranger to the familiar time crunches of modern life, Kyndra tackles the issue head-on in her new cookbook, 30-Minute Ketogenic Cooking. The book features more than 50 of her quickest, most mouthwatering recipes, each of which requires no more than 30 minutes of hands-on cooking time. You’ll be enjoying tasty keto meals in almost no time flat! This book is a game-changer for busy families, overworked singles, and anyone else wishing to adopt and maintain a ketogenic lifestyle without letting food prep, cooking, and cleanup rule their lives. Kyndra has included her favorite fast and flavorful breakfasts, lunches, dinners, and snacks. As in her previous books, every recipe uses only easy-to-source, real-food ingredients and reflects her instantly recognizable flair.
Quick and Easy Keto Recipes
Don't have a lot of time to prepare healthy, low-carb meals for your family? The Ketogenic Diet 30-Minutes Meals is exactly what you need! In this cookbook, you will find dozens of ketogenic-friendly meals, created to help promote your weight loss and health goals. But even more than that, each meal in this book can be on your table in thirty minutes, from start to finish. That includes preparation and cooking.
Benefits of 30-Minute Keto Meals:
- Spending less time in the kitchen
- Eating healthy low-carb meals ready from start to finish in 30 minutes or less
- Getting organized in the kitchen for healthy ketogenic meals
- Recipes that will satisfy even the pickiest eaters
- Making it easy to follow a Ketogenic lifestyle and reap all the benefits
- The many benefits of following a ketogenic diet Lose weight, gain mental clarity, feel energized, and more
- An awesome variety of ketogenic low carb recipes that are easy to prepare
- Each recipe comes with complete nutritional information, so you know exactly what you are eating
Sample Recipes:
- Soups: Spinach, Watercress, and Artichoke Soup; Southwestern White Chicken Soup
- Chicken and Turkey: Creamy Tarragon Walnut Chicken; Spiced Turkey Cutlets with Simple Roasted Vegetables
- Pork: Creamy Ham Frittata; Hazelnut Stuffed Pork Chops
- Beef and Veal: Seared Filets with Spinach Pesto; Pancetta Veal Rolls Over Sautéed Greens
- Fish and Seafood: Soft Scrambled Eggs and Smoked Salmon; Elegant Scallops with Capers
- Vegetarian and Side Dishes: Avocado Tacos; Crunchy Gorgonzola Slaw
Additional 30-Minute Keto Resources
Keep It Quick, Keep It Easy, Keep It KetoNo matter how busy you get, what you’re craving or who you’re cooking for, these keto recipes make it possible to get a healthy, well-balanced dinner on the table every day of the week. Not only is every dish bursting with flavor, but thanks to trained chef Mihaela Metaxa-Albu’s unique approach to the popular diet, you’ll find plenty of low-carb vegetables and whole foods.
Sample Recipes from Other Resources:
- Mediterranean-Style Chicken
- Keto Fried Shrimp with Spicy Mayo and Sweet Chili Sauce
- Pork Tenderloin with Cauliflower Mash
- Teriyaki Pork Stir-Fry
- Thai Fish Green Curry with Broccoli
- Baked Salmon with Asparagus and Dill Sauce
- Indian Butter Chicken with Cilantro-Lime Cauliflower Rice
- Creamy Cajun Shrimp
Mihaela also includes a bonus chapter full of can’t-miss fat bombs such as Strawberry-and-Cream Bombs and rich, fudgy Brownie Fat Bombs, so you can meet your macros and stay in ketosis throughout the day.