Should you ever cut out an entire food group?

You may be considering cutting out specific foods for ethical, environmental, or health reasons. Sometimes there may be a medical reason, such as a food allergy or intolerance (like gluten intolerance in coeliac disease). 

But is it ever a good idea to cut out whole food groups? We look at the pros and cons and offer advice on making sure you get all the nutrients your body needs.  

In this article, we cover: 

• The five main food groups 
• Is a low-fat diet healthy? 
• Is cutting out carbs a good idea? 
• The downsides of plant-based diets 
• How can I check my vitamin and mineral levels? 

 

The five main food groups

The NHS Eatwell Guide divides the foods and drinks we consume into five main groups [1]: 

1. Fruits and vegetables 
2. Starchy carbohydrates, like potatoes, bread, pasta, and rice  
3. Proteins, such as meat, fish, eggs, beans, and pulses 
4. Dairy and alternatives 
5. Fats, such as oils and spreads 

All these food groups have benefits. Eating the recommended proportions of each group should provide all the essential nutrients you need to maintain optimal health.  

 

Is a low-fat diet healthy?

Low-fat diets initially became popular for weight loss because fat contains more calories than the equivalent weight of protein or carbs. Cutting out or limiting fat makes sense to put you in a calorie deficit.  

More recently, evidence suggests that very-low-fat diets may have several health benefits, including: 

• Improving risk factors for heart disease, including high blood pressure and high cholesterol levels 
• Improvements in type 2 diabetes 
• Aiding weight loss for people who are obese 

 

But cutting fat completely from your diet can do more harm than good, as dietary fat is essential to keep your body healthy. 

Dietary fats play several roles in your body, including: 

• Providing energy 
• Supporting cell function 
• Helping your body absorb fat-soluble vitamins, such as vitamins A, D, and E 
• Producing hormones 
• Maintaining body temperature 

 

What’s the difference between good and bad fats? 

Good fats (monounsaturated and polyunsaturated fats) help maintain healthy levels of HDL (good) cholesterol. Bad or unhealthy fats (trans fats and large amounts of saturated fats) can raise non-HDL (bad) cholesterol levels in your blood, increasing your risk of some metabolic and cardiovascular diseases.  

Foods high in saturated fats include: 

• Butter 
• Cheese 
• Red meat 
• Foods high in unsaturated include: 
• Oily fish 
• Vegetable-based oils  
• Nuts and seeds 

Following a Mediterranean diet can help you get a good balance of healthy fats, including heart-healthy omega-3. Omega-3 is a polyunsaturated fat you must get from your diet as your body can’t make it from scratch. If you want to check your omega-3 levels, try our Omega-3 and -6 Blood Test. 

Sources of omega-3 include: 

• Oily fish like mackerel and salmon 
• Nuts and seeds such as walnuts and flaxseed 
• Seaweed and algae 

So, whilst it might be beneficial to reduce your intake of certain types of fats, cutting them out altogether may lead to health issues such as vitamin deficiencies and hormone imbalances.   

Should I switch to foods labelled as low-fat?

Foods labelled as reduced-fat, low-fat, or fat-free aren’t always healthier options. To make them taste good, food manufacturers sometimes replace the fat with sugar, as well as adding salt and other unhealthy ingredients.  

Read the nutrition label to check the sugar and salt content. If a food labelled as low-fat is not much lower in calories than the original product, it might be a healthier choice just to have a smaller amount of the original version.

Is cutting out carbs a good idea?

 

The ketogenic (or keto) diet, which involves cutting carbs in favour of fats, has been hailed as an effective way to lose weight and burn excess body fat.

Normally, your body uses glucose as fuel for energy — either from carbohydrates or added sugars in your diet. On a keto diet, your body is forced to find an alternative energy source and begins to burn fat for energy instead.

Other possible benefits of very-low-carb diets:

• Improved heart health — very low-carb diets have been linked to decreased triglyceride levels [2] (high triglyceride levels can increase your risk of heart disease).  
• Better blood sugar control — cutting carbs, especially refined carbs and sugar, may aid blood sugar control, which is especially helpful for people with diabetes [3].  
• Lower blood pressure — some studies suggest low-carb diets can help if you have high blood pressure. 

Is it safe to cut out carbs? 

Carbohydrates are the body’s main source of energy. They’re also a source of vitamins and minerals (such as calcium, vitamin C, and iron), as well as dietary fibre.  

Three side effects that you may experience if you drastically cut carbs:  

1. Low energy or fatigue 
2. Constipation or digestive discomfort due to a low fibre intake  
3. Vitamin and mineral deficiencies 

In some women, a low-carbohydrate diet can cause irregular menstrual cycles or amenorrhea (the absence of periods). It may also disrupt the production of thyroid hormones over time, leading to fatigue, poor concentration, and irritability.  

How can I cut out carbs? 

It’s usually better to switch to complex carbs rather than ditch them altogether. Simple, refined carbs (like white bread) aren’t big on nutrients and won’t fill you up for long. Also, before you reach for a croissant, it’s worth noting that many processed carbs are laden with fat, salt, and added sugar.  

Complex carbs include wholegrain, unrefined, brown versions to fuel your brain, help you feel fuller longer, and get healthy amounts of fibre and nutrients.  

It’s also important to be aware of free sugars in your diet. Sugar is a form of carbohydrate and free sugars are added to food and drinks, such as cakes, biscuits, chocolate, and some fizzy drinks. The government recommendation for adults is no more than 30g of free sugars per day (roughly equivalent to seven sugar cubes) [4].  

Can cutting out carbs help you lose weight? 

If your goal is weight loss, cutting out carbs may work initially, as it’ll probably give you a calorie deficit. But this may not be sustainable in the long-term, and if you reintroduce this food group, the weight may creep back on.  

Cutting out meat and dairy  

There’s growing interest in reducing meat consumption, with Gen Z being the generation most likely to give up meat in 2023 [5]. Health and wellness, animal welfare, and concern for the environment play a part in these dietary choices.  

Health benefits associated with plant-based eating include:  

• Sustainable weight management 
• Lowered cholesterol levels 
• Reduced risk of diabetes and heart disease 

Dairy and meat products often contain high levels of saturated fats, which increase the risk of heart disease. Reducing the amount of saturated fat in your diet can help to significantly improve your health, especially when it comes to cardiovascular health. The World Health Organisation (WHO) also ranks processed meat alongside smoking as a major cause of cancer [6].   

 

The downsides of plant-based diets

 

Cutting meat and dairy products from your diet could lead to deficiencies in key vitamins, minerals, and macronutrients such as protein, if you don’t switch to alternative sources.  

Deficiencies you should be aware of on a vegan diet include: 

• Vitamin B12 deficiency — vitamin B12 is important for a healthy nervous system and DNA synthesis. B12 is found almost exclusively in animal products. So, it’s important to check your B12 levels; your doctor may recommend a supplement if your level is low. 
• Vitamin D deficiency — fatty fish and fish liver oils are among the best sources of dietary vitamin D. Egg yolks, beef liver, and cheese also contain small amounts. No matter your diet, our main source of vitamin D is sunshine, and it can be difficult to get the recommended amount in the winter. Taking a supplement can help to improve your vitamin D levels. 
• Low iron levels — our bodies don’t absorb iron from plant-based sources as well as from animal-based foods, such as meat and fish. But foods including beans, spinach, and lentils can help you maintain healthy iron levels on a plant-based diet. 
• Calcium deficiency — if you don’t eat dairy products, make sure you’re getting alternative sources of calcium such as leafy greens and tofu. There are also calcium-fortified kinds of plant milk and orange juice.  
• Omega-3 fatty acids — it can be hard to get enough omega-3 if you don’t eat fish, but plant-based sources include walnuts and canola oil. 

Can you get enough protein on a plant-based diet? 

 

It’s possible to get enough protein on a plant-based diet. Meat isn’t the only way to get protein and there are many different plant-based sources. 

Plant-based sources of protein include: 

• Tofu 
• Tempeh  
• Lentils 
• Nuts and seeds  

Plant-based proteins can be a healthier choice in comparison to meat because they contain no cholesterol and are low in saturated fats.  

How can I check my vitamin and mineral levels?

 

Cutting specific food types or groups from your diet may lead to deficiencies in essential vitamins and minerals, so it’s important to check your health status when changing your diet.  

Our range of Nutrition Blood Tests can help you check how your dietary choices are affecting your health. They’ll give you insights into your liver and kidney function, cholesterol levels, diabetes risk, vitamin levels, and more, so you can make sure your body is getting everything it needs to stay healthy.  

Everyone reacts to food differently and there’s no perfect one-size-fits-all diet. It’s a good approach to make any major changes gradually and monitor your health along the way. That way, you can ensure you’re getting the recommended amounts of all the essential nutrients your body needs.  

The Eatwell Guide gives more advice on how much of what you eat should come from each food group, or you could speak to a registered dietician to discuss your diet and health goals before restricting food groups.  

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References 

1. NHS Inform (2023) Eatwell Guide: how to eat a healthy balanced diet. Available at: https://www.nhsinform.scot/healthy-living/food-and-nutrition/eating-well/eatwell-guide-how-to-eat-a-healthy-balanced-diet/ (Accessed: 18 January 2024). 
2. Hu, T. et al. (2012) Effects of low-carbohydrate diets versus low-fat diets on metabolic risk factors: a meta-analysis of randomized controlled clinical trials. American Journal of Epidemiology, 176 (7): S44-54. doi: 10.1093/aje/kws264. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3530364/ (Accessed: 17 January 2024).  
3. Nathan, D.M. (2014) The diabetes control and complications trial/epidemiology of diabetes interventions and complications study at 30 years: overview. Diabetes Care, 37(1), 9-16. doi: 10.2337/dc13-2112. Available at: https://pubmed.ncbi.nlm.nih.gov/24356592/ (Accessed: 17 January 2024).  
4. NHS (2023) Sugar: the facts. Available at: https://www.nhs.uk/live-well/eat-well/food-types/how-does-sugar-in-our-diet-affect-our-health/#:~:text=This%20means%3A,day%20(5%20sugar%20cubes) (Accessed: 18 January 2024). 
5. Statista (2024) Share of adults who plan to not eat meat in Great Britain in 2023, by generation. Available at: https://www.statista.com/statistics/1179923/share-of-adults-that-do-not-eat-meat-among-generations-in-great-britain/ (Accessed: 22 January 2024). 
6. World Health Organization (2019) Cancer: carcinogenicity of the consumption of red meat and processed meat. Available at: https://www.who.int/features/qa/cancer-red-meat/en/ (Accessed: 22 January 2024).