Artificial sweeteners are food additives that duplicate the taste of sugar but usually have fewer calories. Billions of people around the world consume food and drinks containing artificial sweeteners in the belief that they will not contribute to weight gain and will hopefully help them to lose weight. These foods are often labelled as “low sugar”, “sugar free”, “low fat”, “lite” and “diet” making them sound as if they will promote weight loss. However, it turns out that artificial sweeteners can stimulate the appetite and may lead to weight gain.
Why would artificial sweeteners lead to weight gain?
There is a system in the brain that senses and integrates the sweetness and energy content of food. Animal studies have found that after eating a diet containing artificial sweeteners the animals eat about 30% more. This is thought to be because the brain’s reward centre associates the sweet taste with energy content. When the sweet taste is out of balance with energy intake for a period of time the brain recalibrates and increases total calories consumed.
There is now a large body of evidence showing that using sweeteners such as saccharin, sucralose and aspartame may lead to increased food consumption, reduced metabolism after meals, increased weight gain, greater percent body fat, and hyperinsulinemia (excess insulin production which leads to weight gain), compared with animals exposed to plain water and even to sugar-sweetened foods or liquids.
This helps explain why large scale and long term studies on humans find that increases in weight and abdominal fat are observed among participants who use diet sodas and artificial sweeteners daily (1).
Other health problems associated with artificial sweeteners
Furthermore, frequent use of diet drinks and artificial sweeteners has been associated with increased risk of hypertension, metabolic syndrome, diabetes, depression, kidney dysfunction, heart attacks, strokes, cardiovascular disease and total mortality (1,2). It turns out that “sugar free” foods and drinks may be having more negative impacts on health than previously thought.
In addition, the production of low calorie drinks has negative consequences for the environment, with up to 300 litres of water required to produce a ½ litre plastic bottle of carbonated soft drink.
A large number of studies have been carried out on artificial sweeteners with conclusions ranging from “safe under all conditions” to “unsafe at any dose”. It seems that scientists are divided in their views on the safety of artificial sweetener use (3). Whatever one thinks about their safety the use of artificial sweeteners in foods and drinks that are meant to promote weight loss should surely be brought into question. The authors of a study into the effects of artificial sweeteners on the global obesity crisis state that “Far from helping to solve the global obesity crisis, artificial sweeteners may be contributing to the problem and should not be promoted as part of a healthy diet.” (4)
- 1. Physiol Behav. 2016 Apr 26. pii: S0031-9384(16)30184-6. Low-calorie sweetener use and energy balance: Results from experimental studies in animals, and large-scale prospective studies in humans. Fowler SP
- 2. Trends Endorcrinol Metab. 2013 Sep;24(9):431-41. Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements. Swithers SE
- 3. J Pharmacol Pharmocother. 2011 Oct;2(4):236-43. Sugar substitutes: Health controversy over perceived benefits. Tandel KR
- 4. PLOS Medicine, January 2017 Artificially Sweetened Beverages and the Response to the Global Obesity Crisis. Borges M, Louzada M, de Sa TH, Laverty AA, et al.