Effects of Yerba Maté on Metabolism, Satiety, and Mood at Rest and during Exercise

Diet and exercise induce weight and fat loss and lower risks of cardiovascular disease (CVD), diabetes, and other chronic diseases. While diet and exercise remain essential elements of weight loss, nutritional aids such as functional foods and herbal products can enhance their benefits when used concomitantly with lifestyle modifications. Yerba maté (Ilex paraguariensis, Aquifoliaceae) leaves, traditionally used in South America in a water infusion, have antioxidative, vasodilatory, lipid-reducing, antimutagenic, and antiglycation effects. In recent years, this herb has gained attention in North America, Europe, and other regions throughout the world. In vivo studies show yerba maté reduces serum cholesterol, triglycerides, and glucose concentrations, and boosts glycemic control. Furthermore, it affects the expression of glucagon-like peptide-1 (GLP-1) and delays gastric emptying, thus reducing appetite. In humans, it decreases body fat mass and its distribution and also reduces the waist-to-hip ratio.

Yerba maté’s psychomotor and appetite-control effects enhance its weight-loss- and fat-loss-promoting action. A trend towards increased satiety, less hunger, and better mood has been reported. Exercise stimulates fat metabolism, but yerba maté’s thermogenic effects boosted it in indirect calorimetric measures (energy expenditure [EE], fatty acid oxidation [FAO], and respiratory exchange ratio) in resting healthy obese subjects. These authors earlier reported that yerba matéalone or with other components* favors FAO as fuel. Taking 1 g raised FAO ≥20% at an exercise intensity range of 40-70% peak oxygen uptake. This corresponds to maximal fat oxidation (Fatmax) when FAO is at its highest; beyond this point, EE from carbohydrates (CHOs) exceeds that from fats. Exercise at individually determined Fatmax level enhances FAO, insulin sensitivity, and vascular function. This is the first test of yerba maté with steady-state exercise at Fatmax levels versus exercise alone.

For this double-blinded, repeated-measures, crossover, placebo-controlled trial conducted at Sheffield Hallam University in Sheffield, United Kingdom, 21 women aged 18-40 years were recruited. Study dates were not reported. Included subjects exercised regularly in moderate intensity ≥150 min/wk, and had body mass indices <30.0 kg/m2. They had no history of CVD; respiratory disease; high blood pressure (BP); liver or kidney disease; musculoskeletal, neuromuscular, or neurological diseases; or other chronic conditions, including cancer and peptic ulcers; and no family histories of CVD, high BP, or stroke. They did not use medications for these diseases or thyroid, cholesterol, or psychiatric conditions, or hormones, including birth control substances. They were eumenorrheic (had normal or regular menstrual periods), and were not pregnant or nursing. For ≥6 weeks prior to the study, they had not used ergogenic aids or had ≥200 mg/day total caffeine. All were in the luteal phase of their menstrual cycles at baseline. They refrained from the use of supplements during the trial and from strenuous exercise, alcohol, and caffeine for ≥24 h before each session.

Subjects were required to refrain from caffeine use for a minimum of 7 days prior to the initial session. There were 3 sessions, with the second and third held within 7 days of the first. At the first session, subjects were shown the equipment and procedures and assessed for body composition and exercise performance variables, and then they fasted for 3 h. At the second session, they were randomly administered either 2 g (4 × 500-mg capsules) dried, ground yerba maté green leaves (batch no. 17558; Rio Trading Health Company; Brighton, United Kingdom), containing 0.4-1.5% caffeine, or placebo (empty capsules with similar color, size, and appearance), with 300 mL water. At the third session, subjects switched treatments. During exercise, subjects drank another 200 mL water. The second and third sessions were each followed by a 10- to 12-h fast. Subjects kept a 3-day food diary before the second session, recording amounts of all foods, drinks, and snacks consumed. They were asked to replicate that intake for the 3 days before the third session.

At baseline, subjects took an incremental exercise test on an electronically braked cycle ergometer, breathing through a mouthpiece attached to a pneumotach. Heart rate (HR) was measured by a monitor. Body composition was measured using bioelectrical impedance. Cardiorespiratory data were collected during exercise. Beginning at 25 watts for 3 min and increasing 25 watts every 3 min, EE (kcal/min), FAO (g/min), and CHOs (g/min) were calculated at each stage and Fatmax intensity for each subject. This intensity was used in exercise sessions. Subjects took a supplement, rested in a semirecumbent position for 2 h, then cycled for 30 min at self-selected ranges of 60-80 rpm at Fatmax intensity. Appetite and satiety were measured via visual analog scales (VASs). The Profile of Mood States (POMS) questionnaire had a scale of 1-5. Both were completed prior to supplementation, every 30 min during the 120-min rest period, immediately after exercise, and 30 min after.

Out of the original 21 subjects, only 12 completed the study; 9 dropped out, mostly due to time constraints that did not allow them to complete all required testing sessions. In these 12 subjects, yerba maté caused significantly more FAO than placebo during exercise (+23%, P=0.037). This value is strikingly similar to the 24% improvement in FAO these researchers observed in their previous study. The difference was affected by time of exercise (P<0.001), with the greatest difference in FAO at 20-25 min. The area under the curve (AUC) was higher for FAO with yerba maté than with placebo (P<0.001). There was no significant interaction between yerba maté and exercise time. CHOs were not significantly different between treatments but were affected by time (P<0.001), first rising and then falling in both treatments. AUC for CHOs was lower with yerba maté than with placebo (P<0.001).

Total EE was not significantly affected by treatment or time, but AUC for total EE was greater with yerba maté than with placebo (P<0.001). HR did not differ between treatments, but time had significant effects (P<0.001). No interactions were seen. There were significant effects of yerba maté vs. placebo on VAS measures of hunger (P=0.019) and prospective eating (P=0.022), with a trend towards reduced desire to eat (P=0.079) before, immediately before, immediately after, and 30-min post-exercise. Yerba maté had no effect on fullness. These effects are reported in humans for the first time. Yerba maté significantly impacted POMS scores after exercise with better focus (P=0.022), energy (P=0.008), and concentration (P=0.003), and a trend towards more alertness (P=0.066), compared to placebo. Fatigue was not affected. Exercise time did not affect POMS scores, nor were there treatment-time interactions.

The authors conclude that consumption of yerba maté along with exercise focusing on “fat loss” can benefit FAO and improve mood and satiety. Future studies should be longer in order to measure effects over time. No conflict of interest was reported.

*E.g., green tea (Camellia sinensis, Theaceae) extracts, caffeine anhydrous, guaraná (Paullinia cupana, Sapindaceae), yohimbine (from Yohimbe [Pausinystalia johimbe, Rubiaceae]) HCL (hydrochloride), capsicum (from cayenne pepper [Capsicum spp., Solanaceae]), ginger (Zingiber officinale, Zingiberaceae), and bitter orange (Citrus × Aurantium, Rutaceae), among others.


Alkhatib A, Atcheson R. Yerba maté (Ilex paraguariensis) metabolic, satiety, and mood state effects at rest and during prolonged exercise. Nutrients. August 15, 2017;9(8):882. doi: 10.3390/nu9080882.