Coconut oil and weight loss
Over the last number of years there has been a lot of coverage on the potential benefits of coconut oil in your diet. It's been claimed that it can help reduce the memory loss associated with Alzheimer's, improve skin and even boost weight loss and help lower cholesterol. But caution should be exercised in how much you use coconut oil in your diet.
What is coconut oil?
Coconut oil is oil taken from the dried fruit produced by the coconut palm tree. When buying coconut oil you'll see terms like 'virgin' and 'cold pressed'. The term 'cold pressed' meant that the oil has been extracting using machinery rather than heat methods. The term 'virgin' usually refers to it being unprocessed – that is has not been bleached, refined or deodorised. Although there is no industry standard for the term, unlike olive oil.
How can coconut oil boost weight loss?
The basis for the claims are that coconut oil contains high levels of a saturated fatty acid called lauric acid, which is what is known as a medium-chain fatty acid (or MCFA). Compared to long-chain fatty acids (LCFAs) found in other oils, these are considered to be a healthier type of fat. This is because they are more easily absorbed and burned by the body for energy, compared with long-chain fatty acids. These medium-chain fatty acids also appear to be stored differently to long-chain fatty acids, which are stored in the adipose tissue.
What studies have found
Over the last few decades there have been a number of studies on the benefits of coconut oil and medium-chain fatty acids.
- In 1983 an experiment on rats was carried out to test the difference between medium-chain fatty acids and long-chain fatty acids in terms of weight gain. They overfed the rats for six weeks, some with 45% of their calories from MCFAs and others with LCFAs. They found that the rats overfed on MCFA's gained 20% less weight and had 23% less body fat.
- Another small study in 2003 was carried out to analyse the difference in fat oxidation and energy expenditure with MCFAs versus LCFAs. The trial looked at the responses of 17 obese women over 27 days and found that those who consumed medium-chain fatty-acids weren't statistically different but the study concluded that MCFAs as part of a balanced diet could prevent long-term weight gain.
- In 2011, a small study of 20 obese males was conducted to evaluate the impact coconut oil could have on weight loss over four weeks. Their results showed a slight reduction in waist size (2.86 cm or 0.97% from initial measurement) but no impact on overall weight or body mass index (BMI).
The downside of coconut oil
Despite these small studies showing slight benefits to waist size, there is a lack of evidence to suggest long-term weight loss or any significant improvements to Body Mass Index (BMI). According to the Mayo Clinic, while some short-term studies have suggested MCFA's don't raise low-density lipoproteins (LDL) or what is known as 'bad cholesterol', there are limited long-term studies into the impact coconut oil can have on your heart health.
They also highlight how coconut oil is highly calorific, which can signal to your body that it should store more fat. They highlight that even if the stored fat doesn't come from the coconut oil directly, high consumption of it could indirectly encourage fat storage and have the opposite effect of what you're trying to achieve.
Heart UK released a statement in response to media coverage on the benefits of coconut oil, urging caution in its overuse or its aid as a dietary supplement. They highlighted how coconut oil contains approximately 85% saturated fats, which has the potential to raise your overall cholesterol and your low-density-lipoprotein levels. This is extremely high, considering that butter contains 63% saturated fat, and olive oil contains 14% saturated fat. It means that by consuming just two tablespoons of coconut oil in a day, you would be consuming 24g of saturated fatty acids, more than your entire recommended daily allowance for a female, which is 20g per day.
Recommendations for weight loss
While consuming coconut oil in moderation as part of a healthy balanced diet is fine, there is no long-term research to suggest any extraordinary benefits from switching to coconut oil in terms of weight loss. Studies on small scales have shown some benefits to waist size, but not to overall BMI. Heart UK still recommend that to reduce your weight or your cholesterol levels, you should avoid cooking with coconut oil and you should not use it as a dietary supplement.
For long-term weight loss a healthy balanced diet combined with regular exercise is still the most beneficial approach. This should include:
- Lowering the level of saturated fats in your diet and replacing them with unsaturated fats
- Eating more fruit, vegetables and fibres
- Introducing heart healthy whole grains to your diet
- Getting regular aerobic and muscle strengthening exercise