The standard advice to lose weight remains eat less, especially eat less fat and do more exercise. The standard health advice remains cut out saturated fats because they are bad for us. Yet here is a study showing that women lost more weight from around their abdomen when they ate the ‘unhealthy’ saturated fat, coconut oil, than those women who ate ‘healthy’ palm oil. ((Assunção M, Ferreira H.S. et al. Effects of dietary coconut oil on the biochemical and anthropometric profiles of women presenting abdominal obesity. Lipids (2009) 44: 593-601.)) How can this be?
Abdominal fat is rightly considered to be predictive of future health problems, since it shows a high likelihood of fat around the organs inside. So any weightloss diet that reduces waist size has healthy benefits. The 40 women who took part in this study lived in the Brazilian city of Marechal Deodoro. Their ages were between 20 – 40 yrs, and they were all poor. ((Typically, they lived in a 3 room house, without sanitation and the gross family income was less than $1 a day. Poor. Their waist measured more than 88 cm/ 34½”, and the average height was 1.55m/5′ 1″.)) Their usual diet was very carb heavy, reliant on roots, flour and bread. None were pregnant and all reasonably healthy, if rather tubby.
The women were split into 2 groups, one group to use 30ml/2 tbs soy bean oil a day, and the other to use 30ml/2 tbs coconut oil. Soy bean oil is rich in the polyunsaturated fat, linoleic acid whilst coconut oil is rich in lauric acid, a saturated fat. According to the chart below, soy bean oil also sontains a significant amount of oleic acid, the oil that makes up most of olive oil. Myristic, palmitic and stearic acid are saturated fats. So it is quite clear that coconut oil is made principally of saturated fat, whilst soy bean oil contains nearly 74% unsaturated fat.
| Fatty Acid | Composition (%) | |
| Soy Bean Oil | Coconut Oil | |
| Lauric acid | 0 | 49.0 |
| Myristic acid | 0.1 | 17.5 |
| Palmitic acid | 10.3 | 9 |
| Stearic acid | 3.8 | 3.0 |
| Oleic acid | 22.8 | 5.0 |
| Linoleic acid | 51.0 | 1.8 |
| Total | 100 | 100 |
The women followed a diet that reduced the amount of starch, increased the amount of protein (and vegetables), but kept the fat levels the same. Overall, calories were reduced to 1,732 cal per day for both groups. And they were all walked for 50 mins, four times a week by a fitness trainer. ‘Hup two, hup two. Stop slacking at the back – and do stop nattering.’ This was endured by all for 12 weeks.
At the end of the trial period all the women had lost weight, but only the coconut oil group had lost weight from around their waist. In fact, on average the soy bean oil group had actually got slightly fatter around the midrift. There’s more. Cholesterol levels had risen in both groups – rush in the statins – but in the soy bean oil group, the HDL (so called good cholesterol) levels had fallen whilst the LDL levels had risen, whereas the coconut oil group had its HDL cholesterol levels rise – considered a good thing – and their LDL levels rose too, but by nothing like as much.
There is some wiggling about during the discussion, trying to work out why this happened. And the theory put forwards is that cooking with any oil with a similar constitution to soy bean oil – sunflower oil being more prevalent in the West – makes the oil change into a trans fat. These women fried their food in the given fat, and some saved the fat and used it again to save a bit of money. Soy bean oil does not stay stable at heat, whereas a saturated fat does, so it is healthier to fry with coconut oil.
Then there is the vexed question as to why the coconut oil women lost weight around their waist. This was explained by saying that the lauric acid, which makes up the majority of coconut oil is a medium chain fatty acid, and this is not easily incorporated into body fat, as gone into in the linked blog about saturated fat and cholesterol.
True to current dietary tunnel vision, the study does say that these women didn’t eat much meat (they couldn’t afford to!) or fat, so these conclusions cannot be carried over to the average Western diet. But they did think it important to ‘evaluate the effects of coconut oil over a prolonged period’. Seeing as the study was published in 2009, there clearly hasn’t been a rush to change dietary advice yet. But if a slimmer waist is desired, then switching away from the polyunsaturates and adding in such ‘devil’ oils as coconut will actually help, not hinder progress.