What Can't You Eat On A Keto Diet?

Are you considering going keto? If so, you may be wondering what foods to avoid while following the keto diet.

Whether you’re looking to reach a healthier weight or increase your energy levels, the keto diet can —when used alongside a considered workout plan — help you achieve a range of fitness goals. 

But to get the best results, it’s important to know which foods to avoid while following a keto diet. 

In this article, we’ll provide you with a list of foods and beverages you should aim to avoid when going keto. 

What Is A Keto Diet?

To better understand why you can’t eat certain foods on a keto diet, let’s first recap what the keto diet is.

The ketogenic diet is a meal plan that prioritises eating a lot of healthy fats, a moderate amount of protein and very few sugars and carbohydrates.

When healthy fats become the primary energy source rather than sugars and carbohydrates, our bodies enter a metabolic state known as ‘ketosis’. 

Ketosis occurs when our body transforms healthy fats into a readily-available energy source known as ketones. When ketones are produced, our body looks to fats for fuel.

The keto diet has been found to stabilise blood sugar levels, reduce the risk of diabetes and heart disease, increase mental clarity, support weightloss and help you feel fuller for longer.

You can learn more about what a ketogenic diet is in our article ‘Everything You Need To Know About Keto’, and by exploring our educational ‘Keto Hub’.

What Food Can You Eat On A Keto Diet?

So, what food can you eat on a keto diet? 

When going keto, 50-60% of your daily intake should come from healthy fats.

We don’t mean the type you find in your deep-fried fish and chips or highly processed meats. We do, however, mean healthy fats such as:

  • Avocados 
  • Flaxseeds and chia seeds
  • Nuts and nut butters
  • Fatty fish such as cod, sardines and salmon
  • Oils such as olive oil, flaxseed oil and avocado oil
  • MCT oil.

If you aren’t familiar with MCT oils already, they’re a unique super fat sourced from coconuts that support a ketogenic diet. You can learn all about MCT oils in our article, ‘What Is MCT Oil?’. 


What Can’t You Eat On A Keto Diet?

The ketogenic diet works by  limiting your intake of sugar to allow your body to reach and stay in ketosis – the state in which the fat shredding happens. 

Therefore, the foods you can’t eat on a keto diet are the ones that are high in sugars and carbohydrates.

If you do eat foods that are high in sugars and carbohydrates, your body will naturally prioritise them over ketones and you’ll no longer maintain your state of ketosis.

Below is a list of foods you can’t eat on a keto diet in high amounts.

1. Foods To Avoid On Keto: Grains And Gluten-Free Alternatives.

Grains are one of the main food groups you should avoid while on a keto diet. 

Naturally, grains and grain products are high in carbohydrates which will interfere with your state of ketosis. This goes for gluten-free grains too! 

They also have a low nutritional value which means they won’t provide your body with the nutrients it needs.

While you can have a limited amount of carbohydrates without interfering with your ketosis, it’s best to save your daily carbohydrate allocation for foods that are more nutrient dense.

Therefore, you should steer clear of foods made from:

  • Wheat
  • Rye
  • Durum
  • Barley
  • Rice
  • Oats
  • Corn
  • Quinoa.

That means foods you can’t eat on a keto diet include:

  • Breads
  • Cereals
  • Pastas
  • Rice dishes
  • Crackers
  • Biscuits 
  • Cakes.


2. Foods To Avoid On Keto: Starchy Vegetables And Fruits With A High Sugar Content.

Starchy vegetables are high in digestible carbohydrates and break down into glucose when digested. To stay on track, it’s best to swap out starchy vegetables for non-starchy vegetables.

Starchy vegetables you can’t eat on a keto diet include:

  • Potatoes and sweet potatoes
  • Turnips and parsnips
  • Corn
  • Chickpeas
  • Lentils
  • Legumes such as kidney, black and cannellini beans
  • Butternut squash
  • Peas.

The same goes for fruits. Fruits that are high in sugar can spike your blood sugar levels and pull your body out of ketosis. 

Fruits you can’t eat on a keto diet include:

  • Bananas
  • Grapes and raisins
  • Dates
  • Mangoes
  • Pears.

While some fruits such as berries are okay to eat while on a keto diet, you should still eat them in moderation.

3. Foods To Avoid On Keto: Sweetened Dairy Products.

While cheese, milk and greek yoghurt can be enjoyed from time to time, flavoured or sweetened dairy products should be avoided while on a keto diet.

Additional flavourings and additives will often increase the sugar and carbohydrate content in your dairy products and ultimately adversely affect ketosis.

Sweetened dairy products you can’t eat on a keto diet include:

  • Flavoured milk
  • Flavoured yoghurt
  • Aerosol whipped cream
  • Ice cream
  • Sweetened kefir 
  • Sugary probiotic drinks such as Yakult 
  • Sweetened condensed milk
  • Coffee creamer.

4. Foods To Avoid On Keto: High-Sugar Syrups And Preserves.

It may go without saying, but one of the food groups you can’t eat on a keto diet is sugar and sugar alternatives. 

Like fruits with high sugar content, sugar syrups and preserves will spike your sugar levels and derail you from ketosis.

Sugary foods you can’t eat on a keto diet include:

  • Honey
  • Maple syrup
  • Golden syrup
  • Jams and preserves
  • High-fructose corn syrup.

5. Foods To Avoid On Keto: Trans Fats And Processed Polyunsaturated Fats.

Remember when we said not all fats are good fats? Well, it’s true! Not all fats are made the same and while they may not spike your sugar levels, they may still impact your general health and your fitness goals.

High-fat foods you can’t eat on a keto diet include:

  • Margarine
  • Processed meats like salami
  • Fried foods
  • Baked goods
  • Pies and pastries.

Drinks To Avoid On Keto: Juices, Soft Drinks And Some Alcoholic Beverages.

Alongside foods that are high in sugar or carbohydrates, there are many beverages you should avoid drinking while on a keto diet.

Drinks you can’t drink on a keto diet include:

  • Fruit juices
  • Sugary soft drinks
  • High-sugar premixed alcohol drinks
  • Full strength beer
  • Cocktails.

The Takeaway

To get the most out of your keto diet, the best thing you can do is watch your carbohydrate intake.

When you consume enough healthy fats and protein daily, you’ll be able to reach peak ketosis. And the more you can sustain your state of ketosis, the more energy you’ll have and the more fat you’ll burn.

Therefore, foods you can’t eat on a keto diet include anything that’s high in sugars or carbohydrates, such as starchy vegetables, honey, grains or sugary drinks.

It’s also a good idea to steer clear of trans fats. While fatty foods like margarine or processed meats won’t impact your state of ketosis, they will impact your overall health.

If you’re worried about the amount of healthy fats you’re eating in a day, our Melrose MCT is a great staple for your keto diet.

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Cliff Harvey

Cliff Harvey is an author, clinician, researcher and speaker. He is a leader in the field of carb-appropriate nutrition, mind-body healthcare, and the achievement of success in health and performance. Cliff has a PhD in Nutrition(AUT) – research focus was in ketogenesis, ‘keto-flu’ and individualisation of diets, has over 20 years experience as a strength and nutrition coach and is also a registered Clinical Nutritionist as a member of the Clinical Nutrition Association. He also holds qualifications as a Qualified Naturopath (Dip.Nat - NXNZ), a Diploma in Fitness Training (AUT), a Certificate in Health Coaching and Patient Care and is a Certified Kettlebell Instructor (MKA).