SUNDAY SHUTDOWN #12 Fructose makes you fat. But does it though?
It is a commonly asked question that the consumption of fructose contributes to weight gain or is even solely responsible for gaining fat. That for some reason, fructose is worse for you than glucose or lactose. It is highly likely this has stemmed from the rise in overweight and obesity over the last 20-30 years in line with an increase in consumption of fructose, most notably found in fizzy drinks.
Fructose is a form of sugar and is commonly found in fizzy drinks, fruit, agave, honey, salad dressing and desserts. The body cannot use fructose as an energy source straight away and therefore it must break it down into glucose which can then be used for energy or be stored in the liver or muscles.
But does it make you fat?
In a review of the evidence relating to high fructose corn syrup (HFCS) and weight gain conducted in 2007 it was concluded that HFCS does not contribute to overweight or obesity any differently to energy being provided from other food sources. This study was conducted in the USA by an exert panel pulled together by The Centre for Food, Nutrition and Agriculture Policy.
That being said, Morenga et al, 2013, found that consumption of fizzy drinks is related to weight gain, however when this was adjusted for total calorie intake, the statistical significance of this link became weaker. Basically, when they adjusted the diet for calories from other sources there was no observed difference in weight, irrespective of where the calories came from.
More recently, Rosset et al., 2016, investigated if fructose is more involved in cardiovascular and metabolic diseases than calories from other macronutrients, such as protein and fat. They found that there is strong evidence to suggest that sugar consumption is high in obese patients. However, excessive consumption of fructose or sugar, independent of overconsumption of total energy is not solely responsible for weight gain.
The over-riding evidence on “fructose making you fat” is not conclusive. To further add to this, as humans we very rarely consume fructose on its own, we consume foods which contain a variety of different sugars and other nutrients like protein and fat too.
When it comes to fat loss or gain it all comes down to energy balance, which means calories in versus calories out. If you are consuming an excessive level of fructose and have been gaining weight, it’s the total over consumption of calories (or food) driving the gain, rather than the fructose itself.