Why is there this ongoing debate about the merits of low carb/low fat diets for weight loss?
Diet trends are constantly changing, and it’s mainly down to the food preferences chefs and celebs who choose to write and promote recipe and weight loss books. It’s a huge market and readers are hungry for the ‘next diet fad’ to try.
As this study has shown, there are pros and cons of both low carb and low fat diets but the fundamental take home message should focus on the commonalties of the two diets i.e. what the participants were advised to eat, aside from restricting either carbs or fat. All participants were instructed to ‘maximise vegetable intake, minimise intake of added sugars, refined flours and trans fats, and focus on whole foods that were minimally processed, nutrient dense and prepared at home whenever possible’; much like the Mediterranean Diet.
Participants were also ‘encouraged to follow current physical activity recommendations’; which will have affected the health outcomes measured.
In reality there are many roads and indeed no secrets to weight (fat) loss; it requires long-term dietary changes (including reducing calorie intake), regular bouts of physical activity and persistence.
To what extent does this research settle the matter and prove both methods are more or less equal?
The study shows that healthy people should be able to choose if they want to reduce their intake of fats orcarbs in order to manipulate calorie intake to lose weight. BUT, as we saw only this week in the media, people in general aren’t very good at estimating calorie intake; so what makes us think that we are any better at estimating grams of fat and carbs eaten? After all, we eat foods not nutrients!
What this study did show though is that if you have deranged lipid levels then you may want to choose the correct diet accordingly; as the lower fat diet reduced LDL (bad) cholesterol the most, and the lower carb diet reduced triglyceride levels and increased the HDL (good) cholesterol levels the most.
We should also note that no one in the study had diabetes, meaning that findings can’t be translated to this population group.
Is it horses for courses? Different diets suit different people, etc.
The authors conclude that when equal emphasis is given to high dietary quality for both low-fat and low-carbohydrate eating plans, it is not helpful to preferentially direct an individual to one, even if they have a high insulin secretion (where low carb diets historically are promoted).
We should also note that not all participants lost weight during the study; some gained weight and this could be down to the fact that calorie intake wasn’t discussed with them. The individuals who did lose weight reported a decreased energy intake by around 500-600 kcal a day.
All diets work in the short-term at least and the best diet is the one that you can stick to and that suits your lifestyle the most.
I really hope you find my mini interview useful!
You can read more about the study on Examine.com.