With advances in research relating to diet and lifestyle, there has been a growth in knowledge about different ways of eating.^1,2 It has become popular to experiment and find the proper diet that aligns with an individual’s lifestyle, needs and goals.³ Eating keto has become trendy; with approximately 25.4 million searches, the keto diet was the most Googled diet in the United States in 2020.⁴ Individuals report weight loss, higher energy levels, and better cognition and all-round b well-being.⁵ Here, we discuss what keto is, who it may benefit, and provide recommendations for beginning a keto journey.

The ketogenic diet

Eating keto is a way of dieting whereby the intake of carbohydrates and sugar is kept to a minimum, with varying levels of protein and fat. A true definition is a diet with 1 gram (g) of protein per kilogram (kg) of body weight, 10–15g carbohydrates per day, and the remaining calories from fat sources like coconut oil, butter and avocado.⁶

Eating this way pushes the body into ketosis, and the body starts to break down excess body fat to keep up with its energetic and metabolic needs, stimulating weight loss.⁷ Recent research has shown additional benefits, including improved blood sugar control and enhanced lipid profiles, contributing to better overall metabolic health.⁸

The popular ‘Atkins Diet’ created by Dr Robert Atkins in the 1970s was one of the first ketosis-based diets advertised for weight loss and hunger-reduction.⁴ Since then, many other low-carb diets have become popular, varying in recommended amounts of macronutrients.⁶ Interestingly, recent studies suggest keto diets can be beneficial in those coping with long-term disease. Some individuals have been able to reverse or lessen the symptom burden of certain diseases.^{5, 9–11} Although created in the 1970s, keto has become increasingly popular in recent years - with celebrities openly discussing their personal experiences and benefits of eating keto, a ‘keto food industry’ valued at $9.57 billion in 2019.2 has emerged.⁴

What is ketosis?

In non-keto eating, the body relies on carbohydrates for sustained energy production and sugar for immediate energy production.⁷ When excess energy in the form of various sugars is circulating the body, insulin is released from the pancreas to package and store circulating blood sugar as glycogen or adipose tissue, also known as fat, in the body to be later utilised in times of need.⁷ A reduced input of carbohydrates and sugar for 4 days causes a breakdown and depletion of the body’s glycogen stores. From day 5 of keto onwards, the body relies on fat stores for energy production, breaking down fat into fatty acids, inevitably resulting in weight loss.² During this time, ketone bodies are produced in the liver from fatty acids, which carry energy from the liver to the rest of the body to meet its energetic needs.¹²

Keto is thought to result in weight loss because of the breakdown of fat for energy and direct hunger suppression.¹³ In a study, participants were given a 4-week high protein diet; two of those weeks required high carbohydrate intake and two weeks of low carbohydrate intake. Participants reported significant levels of decreased hunger when carbohydrate intake was limited, suggesting ketosis may suppress hunger.¹⁴ However, consuming high amounts of protein suppresses hunger hormones through various molecular endocrinology pathways¹⁵, and further research is needed to confirm if ketosis plays a part in reducing hunger.

Following a keto diet is known to cause weight loss, but surprisingly, it has also shown an improvement in lipid profiles. In fact, one research team has demonstrated that a keto diet is better at improving lipid profiles compared to a low-fat diet¹², possibly because low-carbohydrate diets cause increased breakdown of stored fat.

Getting started with Keto

Key principles of the keto diet:

The main rule of eating keto is to limit carbohydrate intake, which varies across diets.⁶ Not all diets will suit every individual, and careful monitoring and assessment of nutritional status. It is recommended to seek professional help before attempting to change your diet; however, for information purposes, carbohydrate intake can be defined in the following way:⁶

• Very low-carbohydrate (<10% carbohydrates) or 20 to 50 g/d
• Low-carbohydrate (<26% carbohydrates) or less than 130 g/d
• Moderate-carbohydrate (26%-44%)
• High-carbohydrate (45% or greater)

It is essential to note that ‘carbohydrate intake’ is not just rice, potatoes, pasta and bread. It also includes complex carbohydrates, or insoluble carbohydrates like fibre, from fruits and vegetables, legumes and pulses.⁶ It is vital to consume adequate protein from plant and animal-based sources.^14,15 The remaining calories are derived from fat - there are four types of fats: saturated, trans-saturated, mono and polyunsaturated fats.¹⁶ Avoiding foods high in saturated or trans-saturated fats is recommended as these increase the risk of cardiovascular and heart disease. In contrast, mono and polyunsaturated fats reduce these risks.^16,17 Below are examples of foods to consume or avoid while following a keto diet.

Allowed

• Good sources of foods that contain mono and polyunsaturated fats include coconut, avocado, fatty fish, such as salmon and mackerel and nuts, such as almonds, peanuts, cashews, macadamia, walnuts, pecans and seeds like sesame sunflower, pumpkin, hemp and flax¹⁶
• Some dairy foods may be allowed; however, these do contain lactose sugar, which may interfere with your health goals, such as losing weight. Butter and hard cheeses may be allowed because of the lower lactose content^2,18
• Animal protein sources should be grass-fed beef (not grain-fed) and free-range poultry, where possible, due to the slightly higher omega-3 fats.¹⁹ Lean-cut meats, wild-caught fish, organ meats, eggs, tofu and tempeh are other good protein sources¹⁹
• Most non-starchy vegetables are free to eat. These include, but are not limited to, leafy greens (kale, Swiss chard, collards, spinach, bok choy, lettuces), cauliflower, broccoli, Brussels sprouts, asparagus, bell peppers, onions, garlic, mushrooms, cucumber and celery^20,21
• Fruits in small portions like berries. Despite containing carbohydrates, they also contain antioxidants and fibre essential for wellbeing²²
• Other: Dark chocolate (90% or higher cocoa solids), black, unsweetened coffee and tea, herbs, and spices^2,4

Not Allowed

• All whole and refined grains and flour products are added, as well as natural sugars in food and beverages, starchy vegetables like potatoes, corn, pasta, and rice²
• Fruits unless within the limits of carbohydrate restriction; however, all fruit juices are due to the lack of fibre and high sugar content²
• Legumes include beans, lentils, and peanuts due to their high carbohydrate content unless factored into the diet plan²
• Alcoholic beverages²

Tips for success

Making goals

It’s important to start with your intention to change²³ – this could be to lose weight for a vacation, improve your general well-being or feel more energised. These intentions help create SMART goals, which are Specific, Measurable, Achievable, Relevant, and Time-Bound.²⁴ An example of a SMART goal for weight loss is displayed below:

• S – I want to lose a total of 15kg
• M – I want to lose, on average, 0.5-1kg a week
• A – I can use this guide to get me started
• R – So I can avoid risks and illnesses associated with high body fat
• T – I aim to complete this in 6 – 8 months

Preparing mentally and emotionally

With all lifestyle changes, there will be some hurdles to overcome. Having insight and anticipation of what these might be before starting can help an individual prepare ‘rescue packs’ if and when needed.^3,25 These hurdles will be highly variable from person to person. Still, due to the restrictive nature of the keto diet, it can be difficult to part with carbohydrates, especially as they contain staple foods loved by most people. Sometimes, individuals find it hard to adapt to the permissible foods in their diet. Some coping strategies include making pizza from almond flour-based dough or substituting rice for cauliflower rice.⁴

Clearing out non-keto foods from the pantry

This can be a way to prepare physically. It is highly recommended that all unsuitable foods be cleared out, making physical space for permissible foods. This visual of space may help you feel more motivated and shift your psychology to a more optimistic one, ultimately enabling success in reaching your goals.^3,26

Basic shopping list for keto-friendly foods

If you feel less motivated or disciplined, preparing and sticking to a shopping list will help you avoid any temptations. Alternatively, online shopping with a pre-set basket can simplify and nullify any potential risk of derailing from your diet.^23,27

Staying hydrated

It is expected to confuse hunger with thirst. Try drinking 500ml of water when you feel hungry and reassessing in 30 minutes. Also, keep track of your water intake, aiming for 3 litres a day unless told otherwise by a healthcare professional.²⁸

Finding support and community

Joining keto groups online is extremely helpful in the initial stages of starting a new diet. They can help with recipes, valuable tips, support and friendship. Later on, when you’ve built knowledge and confidence, sharing your experiences to help others and connect with the community can be a way to add purpose to your goals.₂₉

Tracking progress and adjustments

Importance of tracking food intake and ketone levels

Tracking Macro and Micronutrients

Tracking macro and micronutrients becomes important when switching to a restrictive diet. Apps have been developed to help with this and simplify calorie counting. Learning and being aware of your food's nutritional and caloric values contributes to health knowledge and empowerment.³⁰

 Signs of progress beyond weight loss

Research suggests following a keto diet can help reduce disease symptom burden, increase energy levels, increase learning and memory, and improve skin appearance whilst also having potential anti-ageing benefits. Being mindful of these positive changes can help fuel motivation and increase the likelihood of successfully reaching health goals.^5,11

Making adjustments based on individual needs and goals

An individual can come across various points where help from a professional is needed, for example, not losing any weight, continuous keto flu symptoms, or reaching a plateau. These are beyond the scope of this article, and you are advised to seek professional help.^24,29

Awareness before starting a keto diet

Dealing with keto flu

When the body switches from using carbohydrates as the main energy source to ketones, it can cause a wide range of symptoms colloquially named ‘keto flu’.^2,4 These include headache, fatigue, nausea, dizziness, insomnia, brain fog, gastrointestinal discomfort, a change in bowels, decreased energy, feeling faint and palpitations. Symptoms are thought to peak in the first week but resolve by week 4 at the latest; however, it is important to seek medical advice if there are any health concerns.

Understanding potential risks and contraindications

Individuals who have been diagnosed with diabetes or are taking insulin or oral hypoglycaemic agents are at an increased risk of severe hypoglycaemia if their medications are not appropriately adjusted before and during a ketogenic diet. It is highly advisable these individuals commence a ketogenic diet with guidance from a healthcare professional for the duration of the diet.

Keto diet is contraindicated in those who have pancreatitis, liver failure, disorders of fat metabolism, disorders involving carnitine such as primary carnitine deficiency, carnitine palmitoyl transferase deficiency, carnitine translocase deficiency, porphyrias, or pyruvate kinase deficiency.^2,5

Additionally, individuals following a ketogenic diet should be aware that there is a rare chance they may experience a false positive on an alcohol breath test due to the conversion of acetone to isopropanol by hepatic alcohol dehydrogenase, resulting in an inaccurate reading.^2,5

Long-term considerations for sustainability

Research has demonstrated that it is safe to follow a keto diet for up to two years and continue to see beneficial results; however, research beyond this timeline is limited, and its safety cannot be guaranteed.^2,5

Known long-term adverse effects include

• Digestive issues: High-fat, low-fibre diets can cause digestive problems, such as constipation, diarrhoea, and bloating
• Kidney stones: A high-fat, low-carbohydrate diet can increase the risk of developing kidney stones³¹
• Heart disease: A ketogenic diet can increase the risk of heart disease if consuming a high level of saturated fat and not enough fibre³¹
• Muscle loss: Rapid weight loss on a ketogenic diet can lead to muscle loss, negatively impacting athletic performance
• Cognitive decline: The effects of low-carbohydrate diets on brain metabolism can potentially lead to cognitive decline^5,10
• Nutrient deficiencies: Keto diets are very restrictive and can lead to inadequate intake of essential vitamins, minerals, and phytochemicals³¹

Consulting with a healthcare professional before starting keto

It’s advisable to consult with a healthcare professional before starting keto, especially if you have multiple co-morbidities or take multiple medications. Some benefits of talking with a professional are listed below:

• Depending on the health goals, specific numerical data can be collected at the start, including weight, BMI, waist circumference, blood pressure, various blood tests and metabolic parameters that can be rechecked periodically to confirm you’re on the right track, highlight improvements in health or need for adjustments
• Letting your doctor know of this change can aid in managing acute symptoms or illness. For example, headaches can be easily attributed to keto flu, avoiding unnecessary testing or referrals, or similarly, when to refer if symptoms are severe or ongoing
• The doctor can refer to a dietician or nutritionist where appropriate
• Individuals with diabetes are strongly advised to have frequent follow-up appointments with their doctor for hypoglycaemia awareness and frequent monitoring of their medications
• Some healthcare professionals are highly educated in nutrition – this allows individualised plans and monitoring³¹

Summary

Embarking on a keto journey can be difficult but rewarding, with multiple benefits to health and well-being. Sustainable weight loss lowers an individual’s risk of serious health complications in the future while promoting health education and empowerment. Starting to eat keto can be a way to meet new people and find a new sense of support and community, improving the individual's mental health, a key aspect in successfully reaching their health goals.

The need for professional guidance from an appropriately qualified individual should not go unnoticed and is recommended before starting the keto journey. Multiple keto resources exist online, but their accountability is unknown. Therefore, it is advised to do your own research and due diligence or seek professional support for further guidance.