This on-trend way to eat has soared in popularity in recent years with its rep of helping people to lose weight thanks to its high-fat and low-carb methods.
Keto diet for beginners: how does the ketogenic diet work?
The ketogenic diet, or keto diet for short, is a high-fat and low-carb plan that aims to turn your body into a metabolic state called ketosis. It’s quite similar to the famous Atkins diet and other low-carb diets that have gained popularity in the last few decades.
Ketosis is where your body burns fat, rather than carbohydrates for fuel. The body usually opts to burn glucose, a sugar found in carbohydrates, for fuel, but if there’s no carbohydrates, the body’s next option is fat. Ketosis also allows fat to be transformed into ketones in the liver to supply energy to your brain.1
Changing to a keto diet, means the fat that you consume, or that is stored, is burnt. This is why the keto diet has become a favourite with those looking to lose excess pounds.
It’s worth noting that the body takes a few days to switch from choosing to burn glucose, to fat, so results aren’t instant.
Is going into ketosis good for you? And are ketogenic diets safe?
Ketosis is natural – the human body is built to do it, but is it really good for you?
Your body enters the metabolic state of ketosis when it is predominantly using fat as fuel for your body and brain – causing a high concentration of ketosis in the blood.
The cells in our bodies usually prefer to use glucose (blood sugar) as fuel as it is usually much easier to access. However, when you limit your carb intake, your body has no choice but to dig into its fat stores and use that as energy instead. This also happens naturally to some extent during infancy, pregnancy, fasting and starvation.2,3,4
It’s only in recent years that some have us have started ‘forcing’ ketosis to happen. Following a keto diet to remain in the state of ketosis has its benefits and risks. Like with any diet, it will suit some people and won’t suit others, but the actual state of ketosis is completely natural and people have been ‘doing it’ for centuries.
What are the benefits of keto diet?
Keto can be pretty intense – especially if bread, pasta and other grains were your favourite things to eat! Considering the gravity of that sacrifice, the health benefits should be pretty good, right? See for yourselves. Here are some of the best ketogenic diet benefits:
Ketogenic diets and weight loss
Eating lots of fat to lose fat is understandably quite a difficult concept to get your head around. For decades we have been fed the rhetoric that low-fat = good and high-fat = bad, so when keto came on the scene in a big way, so did the confusion.
- One study found that people lost 2.2 x more weight than other participants on a low-fat, calorie-restricted diet.5
- Another study found that people following a keto diet lost 3 x more weight than one recommended by the organisation Diabetes UK.6
Here are some reasons why the keto diet is so successful for many wanting to lose weight:
- Appetite control and less cravings: fats and proteins tend to take longer than carbs to digest– especially simple carbs like sugar, white bread, normal pasta, etc. The keto diet is full of healthy fats and protein with very little carbs, which can help control your appetite and cravings and help you to feel fuller for longer – win!7
- No calorie counting or tracking: although the ketogenic diet plan may seem difficult to follow at first, once you’ve got your head around which foods to eat and which to limit in order to keep your body in ketosis, you’ve already done the hard part. There’s no real need to count calories or track your food intake, you just stick to the plan and the weight loss should follow.8
- Gluconeogenesis: the process of converting fats and proteins into carbs for your body to use as fuel may help to burn more calories.9
- Food elimination: most people following a keto diet for the first time will have to pretty much throw their normal diet on its head. The elimination of certain food groups will mean your typical cakes, biscuits and crisps are often off the menu, so this may help you reduce your overall calorie intake, which is essential for fat loss.
- Increased fat burning: following a keto diet alters your metabolism and has been shown to increase the amount of fat your burn all throughout the day – whether you’re sweating it out exercising or lazing around on the sofa – can’t complain at that, can you?!10
Are there different types of ketogenic diets? And what ketogenic diet is best for me?
Yes! There are a few different versions of the ketogenic diet, including:
- SKD – Standard ketogenic diet: this is the typical keto diet that people are referring to when they talk about ketogenic diets. It’s a super low-carb, high-fat and moderate-protein diet that typically contains 5% carbs, 20% protein and 75% fat11
- CKD – Cyclical ketogenic diet: a favourite for bodybuilders and athletes who may struggle to get all the energy they need to train effectively through a keto diet, the CKD diet adds in periods of ‘carb refeeds’, e.g. they follow the standard keto diet for 5 days then allow themselves 2 high-carb days, then repeat the whole cycle again.
- TKD – Targeted ketogenic diet: another favourite for athletes and those with a strenuous training routine, the targeted ketogenic diet allows you to eat some carbs around your workouts.
- High-protein ketogenic diet: just keto with more protein, this version of a keto diet typically advises you to replace some of your dietary fats with protein. The ratio often looks like: 60% fat, 35% protein and 5% carbs
Most of the things we will discuss in this article will be referring to the standard ketogenic diet. However, as you can see above, many of the main principles of keto apply to all of these diets so you should be able to adapt any information quite easily to each one.
Keto diet foods: What do you eat on a keto diet?
A keto diet is made up of around 75% fats, 20% protein and 5% carbs.
To kickstart ketosis, 20g, and no more than 50g, of carbs should be eaten per day. Minimise potatoes, pasta, bread and rice. Carbohydrates are also in alcohol, sweets and fizzy drinks in the form of glucose and sugars. Fruits, especially the sweeter ones, contain carbs; a small banana has around 20g of carbs.
A normal keto meal plan is packed with the following foods:
- Meat: steak, red meat, sausage, ham, chicken, turkey and bacon
- Fatty fish: trout, salmon, tuna and mackerel
- Butter and cream: grass-fed varieties are best, if possible
- Eggs: look for omega-3 eggs if you can
- Cheese: choose unprocessed cheeses like goat, cream, cheddar, mozzarella and blue
- Nuts and seeds: walnuts, almonds, pumpkin seeds, flax seeds, chia seeds
- Avocados: whole avocadoes or home-made guacamole
- Healthy oils: coconut oil, extra virgin olive oil, avocado oil
- Low-carb vegetables: read the next section for examples
Can you eat vegetables on the keto diet?
Veggies aren’t off the menu – yay!
Ketogenic diet vegetables include: cauliflower, cabbage, spinach, courgette, lettuce, cucumber, asparagus and kale are all keto dieters go-tos thanks to their low carb content. Cook your veggies in butter and drizzle salads with oil to increase the fat content. Peppers, green beans, broccoli and sprouts also are a fave, but do have a higher carb content.
Can you do a vegan or vegetarian keto diet?
Yes! The main source of fat in a standard keto diet is from meat and oily fish, however vegetarians can do the keto diet by substituting with increased dairy products, eggs and meat alternatives.
If you opt for a vegan keto diet, make sure to eat the following ketogenic diet foods:
- Vegan ‘meat’: tofu, tempeh, seitan, pea protein faux meats, soya faux meats and any other low-carb, high protein vegan ‘meat’
- Mushrooms: try to find ‘meaty’ varieties like king oyster, shiitake, chestnut, etc. but normal ones will do fine too!
- Leafy greens: kale, spring greens, spinach, etc.
- Above ground vegetables: cauliflower, courgettes, broccoli
- High-fat alternatives to dairy: replace dairy with vegan coconut or soya-based yoghurts, creams and cheeses
- Low-glycemic impact berries: raspberries, blackberries, blueberries and similar
- Sea vegetables: kelp, dulse, bladderwack, etc.
- Fermented foods: kimchi, sauerkraut and other pickled vegetables
Meat-eaters can eat all of these foods too, of course! Read more about what you can eat on a ketogenic diet as a vegan here.
Foods to avoid on the keto diet
Reduce or eliminate the following foods if you’re eating keto:
- Sugar-laden foods: fruit juices, fizzy drinks, cake, ice cream, smoothies, sweets, milk chocolate, etc.
- Starches and grains: rice, pasta, cereals and other wheat-based foods
- Fruit: avoid all fruits except low-glycemic impact berries like blueberries and strawberries
- Legumes and beans: chickpeas, kidney beans, black beans, lentils, peas, etc.
- Tubers and root vegetables: white potatoes, sweet potatoes, parsnips, carrots, etc
- Diet / low-fat products: avoid these as they are normally processed and high in carbs
- Some sauces and condiments: check the nutritional information of your favourite sauces and condiments because some could be very high in sugar
- Unhealthy fats: cut back on your use of processed vegetable oils, mayonnaise, etc.
- Sugar-free ‘diet foods’: sugar-free products are highly processed and tend to be high in sugar alcohols, which have been seen to affect ketone levels so it’s best to avoid
- Alcohol: most alcohol has a very high carb and sugar content, which means they would throw you straight out of the ketosis state
Keto meals: An example ketogenic diet menu
If you’re thinking of trying the keto diet, but unsure of what a typical day’s meals could look like, here’s some ketogenic diet meal plan inspiration to get you started, with options to add meat if you aren’t a veggie.
Cheese and mushroom, 3-egg omelette cooked in butter. Option: Add fried bacon.
Salad bowl with avocado, grilled halloumi, grilled courgette, spinach, lettuce, cucumber with sour cream. Option: Add seasoned chicken grilled in coconut oil or butter.
Salmon fried in coconut oil served with asparagus and broccoli topped with melted butter. Option: Add grated cheddar cheese.
Raspberries or blueberries with whipped double cream, topped with chopped pecans.
Keto diet snacks
Keto diet side effects
Keto flu is the most common side-effect people experience when adapting to the ketogenic diet. Symptoms like fatigue and fogginess are common in the first few days as your body gets used to eating little-to-no carbohydrates.12 To tackle keto flu, make sure you drink plenty of water and get plenty of sleep.
Can you exercise on the keto diet?
Yes, you are able to exercise while following the keto diet. However, if you’ve just made the transition to keto, you may find that your body may struggle to complete certain activities.
When taking part in high intensity exercises like circuits and sprinting, your body looks for something to burn quickly, which is usually carbohydrates. And, seeing as the keto diet limits the amount of carbs, you may find high intensity workouts a little more difficult. Avoid HIIT and circuits while your body gets used to restricting carbs.
Low intensity cardio burns more fat to fuel your body. Try swimming, jogging and cycling. If cardio isn’t your thing, strength training is also an option – try fewer reps with lighter weights to see how you fair.
Before you do any exercise, it’s important to ensure you’re eating enough, both calories and fat. If you already supplement your diet with sports products, check the carbohydrate content on the labels. There are also specific keto diet friendly supplements that you could also try to fuel your next workout.
Not sure if the ketogenic diet plan is for you? Discover which diet is for you here.
Last updated: 6 November 2020