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Reasons to follow a low-carb diet

Tamara Willner
Written by

Tamara Willner

Medically reviewed by

Fiona Moncrieff

7 min read
Last updated May 2024

Here are the main reasons to try a low-carb diet: 

  • Lower-carb diets have been shown to have a positive effect on weight loss.
  • Many trials have shown that you can lose weight without counting calories while doing lower-carb.
  • Lower-carb diets have been shown to be effective at supporting people living with type 2 diabetes.
  • The NHS now funds low-carb interventions across the UK to support type 2 diabetes management.
  • Lower-carb diets may help to prevent heart disease by protecting the artery wall from excessive exposure to high glucose levels.

Everyone is unique, and there is no magic diet that will suit everyone. As we are constantly bombarded with misleading diet-related information, it can be confusing to know whether to adopt a low-fat, low-carb or ignore it all.

A low-carb diet can have many health benefits, from weight loss to the prevention and management of chronic diseases.

This research-based guide will explain why we believe a lower-carb diet results in the most weight loss and provides the most health benefits while remaining a sustainable way of eating in the long term.

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What is low-carb?

There is no official definition of a ‘low’ or ‘lower’ carb diet, which can get confusing.

Research often uses many different classifications, but as a general overview, a lower-carb diet is one where between 20-30% of your overall daily energy intake comes from carbs. This is roughly <130g of carbs (total) per day.

To put this in context, the following examples are one serving of complex carbohydrates and contain roughly 15g of carbohydrate:

  • 80g cooked or 1⁄2 uncooked medium potato or sweet potato.
  • 1 thin slice of wholemeal or wholegrain bread.
  • 1⁄2 wholemeal pitta bread or bread roll.
  • 1⁄2 wholemeal wrap.
  • 20g uncooked or 50g (roughly 1⁄2 cup) cooked brown rice or wholewheat pasta.
  • 20g raw wholegrain cereal, oats, or shredded wheat (approx. 1/3 cup); or 1 wheat biscuit.

When you do eat carbs, you should opt for higher fibre carbohydrates (for example, sweet potato, oats, or wholewheat pasta).

These have a larger molecular structure than carbohydrates with less fibre (for example, white rice, white bread, or white pasta). Fibre makes us feel fuller for longer and has many other health benefits.

If you are following a lower-carb, balanced diet aim to have 1-3 servings of complex carbohydrates per day.

Key points:

  • A lower-carb diet is roughly defined as <130g per day of carbohydrate.
  • When choosing carb sources, opt for complex carbs, e.g. sweet potato.

Why not eliminate carbs?

Following a lower-carbohydrate diet essentially means decreasing, but not eliminating, our intake of foods containing carbs.

This naturally means we are increasing the amount of protein (e.g meat, fish, or eggs) and fat (e.g. olive oil, avocado, or nuts) in our diet.

It’s important to note that there is a difference between a ‘low/lower carbohydrate’ diet and a ‘ketogenic’ diet.

The ketogenic diet (keto) is high in fat and almost eliminates carbs. By doing this, the body is deprived of its primary fuel source, glucose.

The body then creates new metabolic pathways and functions using fatty acids from fat stores and dietary fat intake.

Over time, ketones which are produced from the breakdown of fat, will start to be used by the brain for energy instead of glucose. This process is called ketosis.

While this may sound ideal, the keto diet can be challenging to follow effectively in the long term. It’s much more restrictive, and one ‘slip up’ will temporarily take you out of ketosis.

Overall, it seems that a lower-carb diet, rather than keto, is the most sustainable for most people to follow in the long run.

Key points:

  • Low-carb diets are different from the keto diet (which eliminates carbs)
  • In the long term, keto is very difficult for most people to stick to, and the best diet is one that you can keep up.

Prevention or management of type 2 diabetes

There are several convincing theories of how type 2 diabetes develops. Although different theories disagree on whether insulin resistance or weight gain comes first, many include excessive carbohydrate consumption as a factor in developing type 2 diabetes.

Maintaining stable blood glucose levels is essential to prevent complications associated with diabetes.

As carbs have the most significant impact on our blood glucose levels, reducing our intake of carbohydrate-containing foods will reduce the amount of glucose entering the bloodstream in the first place.

This explains why this diet has always been involved in preventing and treating type 2 diabetes.

Recent studies have found consistent benefits in improved blood glucose control, weight loss, and sustained medication reduction when participants followed a low-carb diet.

It’s also been shown that the low-carb diet had a high adherence rate after 12 months, suggesting it’s a more sustainable way of eating in the long run.

Key points:

  • Excessive carb consumption is a common factor of the leading theories of type 2 diabetes development.
  • A low-carb diet can improve blood glucose control and aid weight loss, which are both important in the prevention and treatment of type 2 diabetes.

Weight loss

The most researched area in the ‘low-carb’ space is weight loss. Since being overweight or obese is a risk factor for type 2 diabetes, it’s essential to consider how effective a low-carb diet is for weight loss.

Low-carb leads to weight loss because protein and fat are more filling than carbs.

Higher protein and fat intake also helps keep our blood glucose (sugar) levels stable throughout the day.

This increase in satiety and reduction in blood glucose fluctuations reduces overall hunger and therefore lowers our overall food intake throughout the day.

Low-carb is also thought to help with weight loss by lowering insulin. Insulin is the hormone responsible for encouraging fat and muscle cells to absorb glucose from the blood, but insulin also promotes fat storage in the body.

When we eat a high-carb diet, the body must release more insulin to take the glucose out of the blood.

So, looking at this process simply: 1) we eat more carbohydrates, 2) these release more glucose into the bloodstream, 3) we need more insulin to get the glucose into the cells, 4) this increased insulin response leads to increased fat storage and weight gain.

A simplified infographic explaining how eating high-carb can promote fat storage.

Many studies have shown that low-carb diets result in rapid weight loss in the first 6 – 12 months.

Initial weight loss is partly due to water loss, but fat loss also occurs. In terms of maintaining this diet in the long run, research suggests that a low-carb diet is the most effective way to lose weight and keep it off.

A study comparing the weight loss over two years between low-fat, low-carb, and Mediterranean diets demonstrated that all diets produce short-term weight loss, with low-carb producing the most.

At the two-year mark, the low-carb group had maintained weight loss significantly more than the low-fat group.

Graph depicting weight loss over 2 years for a low-fat, low-carb and Mediterranean diets.

Key points:

  • Low-carb diets may lead to weight loss as protein and fat are more filling, leaving you satisfied for longer.
  • Low-carb diets also reduce the amount of insulin in your body, resulting in less fat storage.

Lowering the risk of heart disease

It was previously thought that increasing fat in the diet (as naturally happens when following a low-carb diet) might negatively impact our cholesterol levels and increase the risk of cardiovascular disease (CVD).

Research studies have shown that fat intake in the diet can affect cholesterol levels.

However, large meta-analyses have found no relationship between saturated fat intake and CVD or mortality rates.

This suggests that lowering carb intake and replacing it with increased protein and fat will not increase the risk of CVD as previously thought.

To further support this, a recent Prospective Urban Rural Epidemiology (PURE) study, involving over 135,000 participants worldwide also found that populations with higher fat intake had reduced mortality rates.

It’s essential to remember that this was an observational study, so we cannot draw causal conclusions from it. However, this study makes the belief that increased fat intake leads to increased mortality much less likely.

One theory why low-carb diets reduce cardiovascular disease risk is that they help protect the lining of the blood vessels.

A slippery, slimy layer inside our blood vessels looks like a billion tiny hairs under a powerful microscope called the Glycocalyx.

The function of this layer is mainly to protect the underlying blood vessel from damage and to prevent blood clotting.

Research, published by the American Diabetes Association, suggests that high blood sugar (as a result of high carbohydrate intake) significantly reduces this protective layer resulting in damage to the lining of the blood vessel.

The effect of sugar on heart disease.

Key points:

  • Contrary to previous beliefs, lowering carb intake and increasing protein and fat intake does not increase your risk of heart disease.
  • A suggested theory of why low-carb diets protect against heart disease is that they help to protect our blood vessels.

Tips on how to eat lower-carb

Making simple swaps for the carbohydrate element of your meal to low-carb foods is an excellent way to keep enjoying the food you love while still reducing the carb content. Here are some of our favourite swaps:

  • Swap rice for cauliflower rice
  • Swap spaghetti for courgetti (spiralised courgette)
  • Swap mashed potato for cauliflower mash
  • Swap noodles for zoodles (spiralised courgette)
  • Swap potato chips for celeriac chips
  • Swap tortilla wraps for lettuce cups
  • Swap roast potatoes for roast carrots
  • Swap potato crisps for kale crisps

For more tips and specific meal plan ideas, look at our guide on low-carb recipes.

Key point:

  • Eating lower-carb does not mean sacrificing the food you love, just make simple swaps for the carb element of the meal.

Take home message

  • There are many compelling reasons to adopt a low-carb diet.
  • All of the leading theories of the development of type 2 diabetes include excessive carb intake.
  • The best diet for weight loss is one you can stick to long-term, so a lower-carb diet is a good option for many people rather than a keto diet.
  • Evidence suggests that lower-carb diets are the most effective for short- and long-term weight loss.
  • Research shows that a low-carb diet’s natural increase in protein and fat does not increase your risk of heart disease but reduces your risk.
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Write a response


18 September, 2023


Thank you for a very interesting article, particularly the links to the studies.

As someone with atrial fibrillation, I’m mainly concerned with the risk of exacerbating heart disease of course, and am reassured by your conclusion:

“Research shows that a low-carb diet’s natural increase in protein and fat does not increase your risk of heart disease but reduces your risk.”

The question I have is that a study from 2019 reported in the Journal of American Heart Studies, Low‐Carbohydrate Diets and Risk of Incident Atrial Fibrillation: A Prospective Cohort Study ( concluded that:

“In conclusion, we found that a low‐carbohydrate intake was associated with increased risk of incident AF (Atrial Fibrillation), regardless of the type of protein and fat used to replace the carbohydrate. A low‐carbohydrate diet, a way to control weight, should be cautiously recommended, especially considering the potential influence on arrhythmia.”

To a layperson that sounds concerning. Could you explain how the study relates to the research suggesting that the Second Nature version of the low-carb diet is good for the heart?

(To be clear: I think the principles and implementation of the diet are impressive and I highly recommend them. I’m just concerned by the suggestion in the study that it may be bad for those with atrial fibrillation.)



24 July, 2021

It looks from the graph that although initial weight loss is better with low carb the Mediterranean diet finishes with a weight loss that is similar to low carb but just as sustained. In general you’ve made no mention of this and the documented advantages of the Mediterranean diet. Being sponsored to promote low carb?


5 August, 2021

Hi Sam, thanks for your comment. We’re not sponsored to promote particular diets, instead we evaluate and follow the latest scientific evidence. As you said, the Mediterranean diet finishes with a similar weight loss to a low-carb diet after 2 years on the graph. However, you can see that it’s still less weight loss compared with the low-carb diet. A Mediterranean diet is extremely vague and there is no agreed upon definition unscientific literature. Some versions of this diet can be moderate/high carb and some variations can be low-carb. For that reason, it’s challenging to discuss it’s benefits from research, unless the exact nutrient analysis of the diet is included. On top of this, a low-carb diet provides the added benefits of managing our blood sugar levels, which can have knock on effects on our mood, weight, and risk for long-term chronic disease like type 2 diabetes. The sustained weight loss, combined with these benefits, are the main reasons we discuss the advantages of a lower carb diet in this guide.

Helen Davies

24 July, 2021

Thanks for the article about low carb diet. I am totally on board with it, bar occasional cake/biscuit/chocolate binges! I wish I could persuade my husband that this is the way to go. He finds it difficult to give up white bread, potatoes and crisps. I’ll pass your article on to him. And hope he reads

Angela Bardsley

24 July, 2021

Gaining weight due to peri menopause


24 July, 2021

Good advice so far

Annette Smith

24 July, 2021

I have an under active thyroid problem. I exercise gardening and walking did Pilates until pandemic. My weight has increased alarmingly this past year. Do you have a plan that would help please


4 August, 2021

Hi Annette, thanks for your comment! Whilst we recognise that it may be harder to lose weight with an underactive thyroid, our guidelines are designed to help you make sustainable, healthy lifestyle changes. Through following our dietary and exercise recommendations, you’ll be supported to lose weight sustainably and improve your overall wellbeing.

As always, we recommend you continue to manage your condition with your GP alongside the programme.

To take our health quiz, please click here, or email with any questions 🙂

Polly Johnson

24 July, 2021

Have you considered following either Zoe Harcombe or the Two Keto Dudes both of which have online forums or facebook groups?


20 June, 2021

Would this plan be any good for shift workers?


1 May, 2021

Please give me more information of the diet before I commit to it.


13 October, 2020

loved your writing. I came to get to know about a low carb diet and end up being reading four more articles. keep doing your great work

Doreen Steer

24 September, 2020

I believe a low carb diet would help lower my high blood pessure,please send me some diet tips. THANKYOU

Amy Groome

2 October, 2020

Hi Doreen, thanks for your comment! Our programme is designed to help you make sustainable, healthy lifestyle changes. Through following our dietary and exercise recommendations, you’ll be supported to lose weight sustainably and improve your overall wellbeing. The programme also incorporates other aspects of health that will help to improve high blood pressure, including exercise, sleep and mindfulness. You can find out more by taking our health quiz here

Hayley Justice

14 September, 2020

Interesting and informative article I shared with my daughter..
£££ otherwise I would have signed up for sure. Maybe in the new year ( I hope things regarding weight loss in the run up til Christmas)

Pat Warman

15 August, 2020

Thank you for a balanced informative and interesting article giving lots of understandable choices, a clearly written article that calmly lets you decide,other articles are quite forceful without the detail needed and still not knowing what the way forward is,this is enough to whet the appetite !

Jill Hague

27 April, 2020

I am following a low carb diet, and eat a balanced mix of animal protein, plant protein, vegetables and fruit. Where can I find an accurate list of basic foods carb content, per 100grm portion? I mean net carbs, or a separate list of fibre content. Thankyou for a helpful website.

Carole walsingham

17 September, 2019

Thank you for a very informative article,easy to understand,and useful for long term health

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