You can probably speed up a weight loss diet a little by consuming a gram of chilli powder at meals. According to a human study that Dutch nutritionists published in PLoS One, a supplement containing capsaicin – the most active substance in chilli powder – prevents your metabolism from slowing down if you’ve reduced your calorie intake.
Capsaicin [structural formula on the right] is the main substance that’s responsible for the hot taste of chilli pepper. In the body capsaicin interacts with the vanilloid receptor, and this boosts the metabolic rate. This is the reason that nutritionists hope that capsaicin may be a naturally occurring substance that can help against overweight.
The Dutch scientists wanted to find out whether capsaicin could boost the effect of a low-calorie diet on fat loss. They used 19 healthy subjects for their experiments, and gave them capsaicin at mealtimes. The researchers used McCormick chilli powder, which contained 2.45 mg capsaicin, 0,28 mg nordihydrocapsaicin and 1.44 mg dihydrocapsaicin per gram.
The subjects were given 1.03 g chilli powder – which contained 2.56 mg capsaicin – at each meal. Not everyone reacts well to this fairly high quantity, so the researchers selected subjects who were used to eating chilli pepper regularly.
The researchers got the subjects to spend a period of 36 hours in a respiration chamber on four occasions, so that they could measure the subjects’ energy expenditure.
On one occasion the subjects consumed 100 percent of the amount of energy they expended, and took no capsaicin. On another occasion the subjects consumed the same amount of energy, but took capsaicin at each main meal.
On a third occasion the subjects consumed 75 percent of the amount of energy they expended, and took no capsaicin. And on yet another occasion the subjects consumed the same amount of energy, but took capsaicin at each main meal.
The calorie restriction reduced the total amount of energy that the subjects expended, but capsaicin decreased the amount of that reduction.
When the subjects consumed 75 percent of their calorie requirements and did not take capsaicin, they did not start to burn significantly more fat according to the researchers’ statistical calculations. When the subjects took capsaicin at meals there was a statistically significant increase in fat burning.
Capsaicin supplementation did not raise blood pressure.
“In an effectively 20.5 percent negative energy balance, consumption of 2.56 mg capsaicin per meal supports negative energy balance by counteracting the unfavorable negative energy balance effect of decrease in components of energy expenditure”, the researchers summarised. “Moreover, consumption of 2.56 mg capsaicin per meal promotes fat oxidation in negative energy balance and does not increase blood pressure significantly.”
Acute effects of capsaicin on energy expenditure and fat oxidation in negative energy balance.
Addition of capsaicin (CAPS) to the diet has been shown to increase energy expenditure; therefore capsaicin is an interesting target for anti-obesity therapy.
We investigated the 24 h effects of CAPS on energy expenditure, substrate oxidation and blood pressure during 25% negative energy balance.
Subjects underwent four 36 h sessions in a respiration chamber for measurements of energy expenditure, substrate oxidation and blood pressure. They received 100% or 75% of their daily energy requirements in the conditions ‘100%CAPS’, ‘100%Control’, ‘75%CAPS’ and ‘75%Control’. CAPS was given at a dose of 2.56 mg (1.03 g of red chili pepper, 39,050 Scoville heat units (SHU)) with every meal.
An induced negative energy balance of 25% was effectively a 20.5% negative energy balance due to adapting mechanisms. Diet-induced thermogenesis (DIT) and resting energy expenditure (REE) at 75%CAPS did not differ from DIT and REE at 100%Control, while at 75%Control these tended to be or were lower than at 100%Control (p?=?0.05 and p?=?0.02 respectively). Sleeping metabolic rate (SMR) at 75%CAPS did not differ from SMR at 100%CAPS, while SMR at 75%Control was lower than at 100%CAPS (p?=?0.04). Fat oxidation at 75%CAPS was higher than at 100%Control (p?=?0.03), while with 75%Control it did not differ from 100%Control. Respiratory quotient (RQ) was more decreased at 75%CAPS (p?=?0.04) than at 75%Control (p?=?0.05) when compared with 100%Control. Blood pressure did not differ between the four conditions.
In an effectively 20.5% negative energy balance, consumption of 2.56 mg capsaicin per meal supports negative energy balance by counteracting the unfavorable negative energy balance effect of decrease in components of energy expenditure. Moreover, consumption of 2.56 mg capsaicin per meal promotes fat oxidation in negative energy balance and does not increase blood pressure significantly.
PMID: 23844093 PMCID: PMC3699483 DOI: 10.1371/journal.pone.0067786 [PubMed – indexed for MEDLINE]