Asparagus is one of the most popular diet foods and not just for its delicious taste – it is a rich source of antioxidants and considered a SIRT food for its ability to stimulate metabolism and boost weight loss.
How asparagus supports weight loss
Asparagus helps you lose weight in a number of ways. Green and purple asparagus provide as much as 75mg polyphenol antioxidants per 100g serving, including rutin, quercetin and kaempferol which all interact with your SIRTs – proteins which regulate fat metabolism and the speed at which you burn fat to generate energy.
Asparagus also has a diuretic effect to help flush away an excess retained fluid. While on the loo, you may notice that eating asparagus imparts a strong and distinctive odour that resembles rotting cabbage. This is due to the breakdown of a substance called asparagusic acid, but this doesn’t affect everyone. The ability to both produce and detect these smelly products are genetic traits – an estimated 40% of people break down asparagusic acid, and one in two of these are able to detect the smell of these asparagus breakdown products. These traits do not affect the ability of asparagus to help you lose weight, however.
Asparagus antioxidants reduce the breakdown of starch by inhibiting starch hydrolase enzymes. This helps to slow the absorption of glucose to reduce blood sugar swings, insulin release and hunger pangs.
Asparagus contains substances that reduce stress and may help to reduce food cravings and comfort eating. Researchers in Japan have even developed an asparagus-based anti-stress functional food, which was found to lower cortisol levels.
Asparagus has beneficial effects on the liver to increase the production of enzymes involved in metabolising fat and alcohol.
Lastly, eating asparagus helps to fill you up as it has a good content of both soluble and insoluble fibre (8%) to help fill you up. Not only that, asparagus is also surprisingly low in calories, providing a mere 20 kilocals per 100g serving.
Asparagus weight loss studies
Two studies have investigated the effect of combinati supplements that include asparagus extracts.
An asparagus extract was tested as a weight loss supplement in 80 people who were starting a low calorie diet as part of a long-term weight loss program. At the beginning, they weighed, on average, 85kg, with a body mass index (BMI) just broaching the obese range (29.9).
For seven days, the volunteers took a psyllium fibre supplement every morning, had a low calorie meal replacement juice (made from elderberries and elderflower) in place of meals, (plus tablets providing 225 mg dried elderberry powder and 600 mg elderflower extract) and also took 2.7g asparagus powder tablets per day (equivalent to 40.5 g dried asparagus). On this rather odd regime, they only ate 400 kcals per day, divided into four to six portions, and drank at least 3 litres fluid per day. Not surprisingly, they lost an average of 3.2 kilograms in weight, with a reduction in BMI to 28.9 kg/m2 although over a quarter admitted they had not kept strictly to the diet. Those who broken the diet lost an average of 2.5kg compared to those who stuck to the diet, who lost an average of 3.5kg.
They researchers concluded that an asparagus and elderberry based low calorie diet can effectively start a longer term program of healthy eating that focusses on monounsaturated oils (eg olive oil), lots of fruits and vegetables, nuts, bean curd or tofu and a reduced intake of simple carbohydrates and animal fats – ie a more plant-based flexitarian or vegetarian style diet.
While we don’t necessarily recommend following this very low calorie diet approach, even for one week, you can benefit from adding more asparagus to your diet!
Another study involving 98 people who took either placebo or an asparagus based supplement while following a 1,500 kcalorie per day diet and exercise weight loss program. One hour before eating their two main meals, they took a tablet providing extracts of Asparagus, Green tea, Black tea, Guarana, Mate and Kidney beans. Half an hour after eating, they also took a tablet containing extracts of Kidney bean pods, Garcinia cambogia and Chromium yeast. These combinations of botanical ingredients were chosen for their individual ability to aid weight loss, through effects on appetite, hunger, metabolism, fat burning, reduced fat storage and fluid balance.
After 12 weeks, those taking placebo lost around 1kg in fat mass as a result of their 1,500 kilocalorie per day diet and exercise program. Those following the same diet and exercise program, but who also took the asparagus based supplements, lost around 2.5kg in fat mass – suggesting that this combination of botanical ingredients had a significant additional effect.
How to eat asparagus
You can eat asparagus lightly steamed, or roasted, pan seared, grilled or grated raw and added to salads, or tossed into a vegetable based sauce, risotto, stew or soup. One of the nicest ways to eat it is with your fingers, as an appetiser, dipped in a little melted butter with lashings of freshly-ground black pepper.