Diet Program Guide
Ketogenic Diet
Very low carb, high fat — using fat as the body's primary fuel source
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The ketogenic diet is a very low-carbohydrate, high-fat eating approach that shifts the body's primary fuel source from glucose to ketones — molecules produced when fat is broken down in the liver. This metabolic state is called ketosis. The typical macronutrient split is around 70–75% fat, 20–25% protein, and just 5% carbohydrates, translating to under 20–50g of net carbs per day.
Originally developed in the 1920s as a clinical treatment for drug-resistant epilepsy, the keto diet has since become widely adopted for weight loss and metabolic health. Its popularity rests partly on its appetite-suppressing effect — ketones and high fat intake tend to reduce hunger more effectively than high-carbohydrate diets, which can make calorie reduction easier to sustain without feeling deprived.
Keto is one of the more restrictive dietary frameworks, requiring significant changes to food choices and careful attention to carbohydrate content in all foods. Initial adaptation takes one to four weeks and often involves temporary side effects known as the keto flu.
Key Principles
- Keep net carbs under 20–50g per day (net carbs = total carbs minus fibre)
- Fat should make up the majority of calories — 70–75%
- Protein is moderate, not high — excess protein can be converted to glucose
- Prioritise whole food fat sources: meat, fish, eggs, nuts, avocado, olive oil
- Track carbs carefully — many foods contain hidden carbohydrates
- Stay well hydrated and maintain electrolyte intake (sodium, potassium, magnesium)
What to Eat & What to Avoid
✓ Eat freely
- Beef, lamb, pork, chicken, turkey
- Fatty fish — salmon, mackerel, sardines
- Eggs (all styles)
- Hard & soft cheeses
- Butter and cream
- Avocado
- Olive oil, coconut oil
- Nuts — almonds, walnuts, pecans
- Leafy greens, courgette, broccoli
- Cucumber, celery, bell pepper
✗ Avoid
- Bread, pasta, rice, oats
- Sugar and sweets
- Most fruit (high in fructose)
- Potatoes and starchy vegetables
- Beans and legumes
- Milk and low-fat yogurt
- Fruit juice and soft drinks
- Beer and most alcohol
- Cereals and granola
- Low-fat processed products
A Typical Day on Keto
Breakfast
3 scrambled eggs cooked in butter with smoked salmon and a handful of spinach~480 kcal · 35g fat · 32g protein · 3g carbs
Lunch
Large salad with grilled chicken thighs, avocado, feta cheese, olive oil and lemon dressing~520 kcal · 38g fat · 36g protein · 6g carbs
Snack
A small handful of almonds (30g) + 2 slices of cheddar cheese~240 kcal · 20g fat · 10g protein · 3g carbs
Dinner
Salmon fillet pan-fried in coconut oil, served with roasted broccoli and a side of cream cheese sauce~580 kcal · 42g fat · 40g protein · 5g carbs
Who It Suits Best
Keto works well for people who find that reducing hunger and cravings is the main barrier to losing weight, those who prefer structure and clear food rules, and individuals who tolerate higher fat intake well. It's also used therapeutically for epilepsy management and is being researched in type 2 diabetes and metabolic syndrome contexts.
It is less suitable for endurance athletes who rely on glycogen, people who find fat-heavy meals difficult to digest, those with a history of disordered eating, and anyone with kidney disease or a history of pancreatitis (who should consult a doctor first).
Advantages & Disadvantages
Advantages
- Strong appetite suppression
- Rapid early weight loss (partly water)
- Reduces blood sugar spikes
- May improve HDL cholesterol
- Clear, unambiguous rules
- Can reduce cravings for sugar
Disadvantages
- Keto flu during adaptation (1–4 weeks)
- Very restrictive — hard to socialise
- May reduce athletic performance initially
- Long-term data still limited
- Can raise LDL in some people
- Requires careful planning and tracking
Tips & Tricks
- Track net carbs, not total carbs. Fibre doesn't raise blood sugar, so subtract it. A food with 10g carbs and 6g fibre has 4g net carbs.
- Prioritise electrolytes. Keto causes increased sodium excretion. Add salt to food, eat magnesium-rich foods (nuts, leafy greens), and consider a potassium supplement or eat avocados.
- Expect the keto flu. Headaches, fatigue and brain fog in the first week are normal. Drink more water and increase salt intake — most symptoms resolve within 5–7 days.
- Meal prep proteins in bulk. Cook a large batch of chicken thighs, mince or boiled eggs at the weekend so weekday meals are easy without decision fatigue.
- Don't fear fat. A common mistake is eating too little fat while cutting carbs — this leaves you hungry and undersupplied with energy. Fat is your fuel on keto.
- Read labels on everything. Many sauces, dressings and processed meats contain hidden sugars or carb fillers. Check per-100g carb content before buying.
- Keep emergency snacks handy. Almonds, cheese slices or hard-boiled eggs prevent poor choices when hungry and on the go.
Frequently Asked Questions
How long does it take to enter ketosis?
Most people enter a measurable state of ketosis within 2–4 days of eating fewer than 20–50g of net carbs per day, though full fat-adaptation can take 3–6 weeks. Exercise accelerates the process by depleting glycogen stores faster.
What is the keto flu and how do I manage it?
The keto flu refers to a cluster of symptoms — headache, fatigue, irritability, brain fog, and muscle cramps — that occur during the first 1–2 weeks as the body adapts to running on fat instead of glucose. It is largely driven by electrolyte loss (especially sodium). Increasing salt intake, drinking more water, eating potassium-rich foods, and ensuring adequate magnesium usually resolves it within a week.
Can I drink alcohol on keto?
Dry wines (red, white, rosé) and spirits (vodka, gin, whiskey) are very low in carbs and can be consumed in moderation without breaking ketosis. Beer is high in carbs and should be avoided. Be aware that alcohol tolerance is often reduced on keto, and alcohol can temporarily stall fat loss even if it doesn't break ketosis.
Will keto damage my kidneys?
For healthy individuals, there is no evidence that a well-formulated ketogenic diet damages kidney function. However, people with pre-existing kidney disease should not follow keto without medical supervision, as the higher protein and altered mineral excretion can be problematic for already-compromised kidneys.
Can I exercise while on keto?
Yes, and many people do. Strength training adapts well to keto once fat-adaptation is established. Endurance athletes may notice a temporary performance drop during adaptation. High-intensity interval training (HIIT) can be harder to sustain in the early weeks, as it relies heavily on glycogen. Most people report performance returning to baseline within 4–8 weeks.
Free Tools to Support Your Keto Diet
Disclaimer: This guide is for general educational purposes only and does not constitute medical or nutritional advice. The ketogenic diet involves significant dietary changes and may not be appropriate for everyone. Consult a registered dietitian or your GP before starting, particularly if you have diabetes, kidney disease, heart conditions or are pregnant.
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