Low Carb vs. Low Fat: Which is better for your new year resolution?

By Justin Dumrongkulraksa

For decades, dieticians have been heralding low fat diets as the cure for obesity, but recent research suggests that this may not be the case. One problem with a generic lower fat diet is that it encourages people to stop eating fats that are beneficial for the heart along with the detrimental ones. Another problem occurs when people cut back on fat, for they often switch to foods full of easily digested simple carbohydrates such as white bread or sugary soda. A new low carb diet, however, has been  rising in popularity over the past few years in which dieters restrict carbohydrate intake.

A recent study compared the efficacy of a low carb diet versus a low fat diet in a group of 148 men and women.  Compared with participants on the low-fat diet, those on the low-carbohydrate diet had significantly greater proportional reductions in fat mass and greater proportional increases in lean mass. Participants in both groups also considerably reduced their waist circumference, but changes in waist circumference were more favorable in the low-carbohydrate group at 3 and 6 months. Waist circumference, however, did not differ significantly from those in the low-fat group at 12 months.

Photo credit: anastasia r / Foter / CC BY-ND

Photo credit: anastasia r / Foter / CC BY-ND

So how does this work? Well, the answer has to do with how your body’s metabolism functions. Refined carbohydrates, such as sodas high in fructose corn syrup, are rapidly and fully metabolized by the liver. Carbohydrates enter a metabolic pathway called glycolysis to make the intermediates necessary for respiration. One of these intermediates is called Acetyl CoA, and in abundance it is converted into fatty acids. One reason why low fat dieters continue to gain weight after cutting high fat foods is because they turn to carbohydrates to fill their plates, and their bodies convert the excess into fat.

So how does a low carb diet differ?  Fatty acids and proteins are broken down into Acetyl CoA, a ketone body, during states of starvation. The body prefers to use carbohydrates but has the capability to breakdown its own fat stores for energy. When this happens, it is called ketosis. because energy is being harvested from ketone bodies  instead of carbohydrates. Thus, low carb dieters are constantly burning fat from their diet and their bodies throughout the day when compared to low fat dieters.

In addition to burning fat, low carb dieters also avoid consuming food high in simple carbohydrates (i.e. fructose) which, in high daily doses, causes loss of hepatic insulin sensitivity in one 2005 study. Simple carbs can also contribute to cardiovascular disease equally, if not more, compared to saturated fats.

The obesity epidemic has not diminished in the past few years. With so many unhealthy foods available, often at cheap prices, maintaining healthy body weight can be incredibly difficult. While exercising is important to losing weight, changing your diet is the first step. One does not need to exercise as much when not consuming thousands of calories in sugary snacks. As with every diet plan, it does not work for everyone and it does require a lot of work, but hopefully with the ongoing research into dieting, everyone can find the diet plan that works best for them.