RecruitingNAINTERVENTIONAL

Low-carbohydrate Diet and Low-Density Lipoprotein - Cholesterol (LDL-c) Interindividual Variability

This research is investigating how much 'bad' cholesterol (LDL-c) levels can vary among healthy people when they follow a low-carbohydrate diet. While low-carb diets are popular and can help with blood sugar, some people experience a rise in 'bad' cholesterol, which could be linked to heart health risks. By carefully studying healthy volunteers, the aim is to understand why these differences occur. This will help doctors and dietitians give better, more tailored advice about low-carbohydrate diets, ensuring people know if it's potentially beneficial or if it might carry a risk for their heart health.

At a glance

Status

Recruiting

Phase

Sponsor

University of Bath

Enrolment target

Start

05 Feb 2026

Estimated completion

01 Mar 2027

Healthy

What is this study about?

You might have heard a lot about low-carbohydrate or 'keto' diets recently. These diets involve eating very few carbohydrates, which changes how your body uses energy. Some studies have shown that they can be helpful for certain medical conditions, like managing blood sugar for people with type 2 diabetes. Many people, even without a health condition, are interested in trying them out.

However, there's a bit of a puzzle. While these diets can offer benefits, they can also cause some people to have higher levels of a type of cholesterol called LDL-c, often called 'bad' cholesterol. High levels of this cholesterol can sometimes be linked to a higher risk of heart problems. What's even more interesting is that this doesn't happen to everyone – some people's cholesterol stays the same or even improves, while others see a noticeable increase.

This study aims to get to the bottom of this. We want to understand why different people react so differently to a low-carbohydrate diet when it comes to their cholesterol levels. By doing this, we hope to find ways to predict who might benefit from a low-carbohydrate diet and who should perhaps be cautious, especially regarding their heart health. This knowledge could help doctors and dietitians give more personalised and safer advice about diets in the future.

Key takeaways

The study explores how low-carb diets affect 'bad' cholesterol.
It aims to understand why responses vary between healthy people.
Information gathered could lead to personalised diet advice.
Participation involves following specific diets and attending lab visits.
You'll eat provided meals on diet days and have blood and urine tests.
You can stop participating at any time.

Who may be eligible?

To join this study, you need to be at least 18 years old and generally healthy, with a body weight considered to be in a healthy range (BMI between 18.5 and 35). We'll also check your cholesterol and fat levels in your blood to make sure they're not too high before you start.

You wouldn't be able to join if you've recently had big changes in your weight, or if you smoke. We also can't include you if you've been diagnosed with high cholesterol, diabetes, heart conditions, or certain digestive problems. If you have any food allergies or intolerances, or if you're already on a ketogenic diet, this study wouldn't be right for you. Also, if there's any other medical condition or medication you're taking that could affect the study results, you might not be eligible.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you 18 years old or older?
Do you have a healthy body weight (BMI between 18.5 and 35)?
Do you have normal cholesterol and blood fat levels?
Do you not have diabetes, heart disease, or digestive problems?
Are you not actively smoking?
Are you not currently on a ketogenic diet and willing to try one for the study?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll be asked to follow a low-carbohydrate diet and a regular control diet over several separate days. You'll switch between these diets over six different days, with 6 days rest in between each diet day. We'll give you all your meals for the diet days and ask you not to eat anything else. You'll complete three days on the low-carb diet and three days on the control diet.

Before the study starts, you'll visit the lab for some initial checks, including a blood sample and a body scan (DEXA scan) to understand your body make-up. You'll also wear a special wristband for a week to track your usual activity levels. During the study, you'll visit the lab 12 times in total. Each time, you'll come in after not eating overnight. We'll take a small blood sample (about 4 teaspoons) and a urine sample. We'll also ask you to try and keep your physical activity levels consistent throughout the study.

Potential risks and benefits

Taking part in this study could help us better understand how low-carbohydrate diets affect people's cholesterol, which could lead to better diet advice for everyone in the future. You might find out more about your own body's response to different diets. As with any study involving blood tests, there's a small risk of bruising or discomfort. Following a low-carbohydrate diet might have some short-term effects like tiredness or headaches for a short period. Remember, you can choose to leave the study at any time, even if you've already started, without needing to give a reason.

Locations (1)

University of Bath
Verified postcode
Bath, United Kingdom· Recruiting

Common questions

What is a 'low-carbohydrate' or 'keto' diet?

It's a diet where you eat very few foods high in carbohydrates (like bread, pasta, sugar) and focus more on fats and protein.

What is 'bad' cholesterol (LDL-c)?

LDL-c stands for Low-Density Lipoprotein-cholesterol. High levels of this type of cholesterol in your blood can sometimes be linked to a higher risk of heart problems.

Will I have to eat special food?

Yes, on the diet days we will provide all your meals, and you'll be asked to only eat what we give you for that day.

How many times will I have to visit the lab?

You'll have a few initial visits and then 12 study visits in total, spread out over time.

Can I leave the study if I change my mind?

Yes, you are free to withdraw from the study at any point without needing to give a reason.

How to find out more

Bruno Spellanzon, PhD candidate

bs954@bath.ac.uk 447769407954 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.