Caffeine in beverages, like coffee, tea, energy drinks, colas, products containing cocoa or chocolate, and multiple dietary supplements and medications help in weight loss. Caffeine may reduce feelings of hunger and desire to eat for a brief time. It also appears to increase energy use even when you’re at rest. It stimulates thermogenesis, a process through which your body generates heat and energy for digesting food. These properties of caffeine may slightly boost weight loss or prevent weight gain. (https://www.mayoclinic.org/healthy-lifestyle/weight-loss/expert-answers/caffeine/faq-20058459)
Herbal ephedra/caffeine shows body weight, fat reduction, and improved blood lipids without adverse events. (Boozer et al., 2002). In another study, high caffeine intake leads to weight loss through thermogenesis and fat oxidation. It also suppressed leptin in women. A green tea-caffeine mixture improves weight management in habitually low caffeine consumers, partly through thermogenesis and fat oxidation. (Westerterp-Plantenga et al., 2005)
The negative relationship between diabetes risk and ground coffee consumption and regular tea was applied to nonelderly adults who had previously lost weight. (Greenberg et al., 2005) Weight maintenance after 7.5% body-weight loss was not affected by green tea treatment. Habitual caffeine consumption affected weight maintenance in the green tea treatment. (Kovacs et al., 2004)
A dietary supplement containing a low-potency ephedra/caffeine mixture appeared safe and effective in causing weight loss and body fat. It improved several metabolic parameters, including insulin sensitivity and lipid profiles. Such a supplement could assist with weight loss. (Hackman et al., 2006)
The US Congress passed the Dietary supplement health and education Act of 1994. Post that, herbal dietary supplements containing caffeine and ephedrine for weight loss became widespread in that country. Reports of adverse events from consuming these non-prescription supplements led to the restriction on these products use.
Caffeine and ephedrine give equivalent weight loss to Diethylpropion. Superior weight loss was seen compared to dexfenfluramine, another popular weight loss prescription medicine. Adverse events with caffeine and ephedrine are mild and transient. The benefits of treating obesity through these natural compounds are an effective treatment. (Greenway, 2001)
Ephedra, ephedrine, and caffeine increase the risk of psychiatric, autonomic, and gastrointestinal symptoms and heart palpitations. Weight loss benefits from the use of these drugs are modest and short-term. (Shekelle et al., 2003)
An earlier study claims that ephedrine/caffeine, in combination, is effective. In contrast, caffeine and ephedrine separately are ineffective for the treatment of human obesity. (Astrup et al., 1992) Gains from catechins or epigallocatechin gallate (compounds found in green tea) and caffeine given as a mixture have a small positive effect on weight loss and maintenance. The result of this study suggests that habitual caffeine intake may influence the outcome of catechins. (Hursel et al., 2009)
A combination of ephedrine, caffeine, and aspirin is well tolerated in otherwise healthy obese subjects. It supports modest, sustained weight loss even without prescribed caloric restrictions. These may be more effective in conjunction with the limitation of energy intake. (Daly et al., 1993) Green tea- caffeine mixture was effective independently in causing weight loss. (Hursel et al., 2009) A synergistic effect in the ephedrine/caffeine combination helps maintain weight loss. (Toubro et al., 1993, Westerterp-Plantenga, 2010)
Ingestion of weight loss supplements in a healthy overweight population did not produce any noticeable cardiovascular side effects. (Kalman et al., 2002) This finding may help alleviate some of the concerns about using these supplements. But free unsupervised use of weight loss supplements is not advocated.
Monoselect Camelia and Greenselect Phytosomes are tea-based proprietary product formulations. Greenselect Phytosome is a lecithin formulation of a caffeine-free green tea catechin extract. It was beneficial for weight/waist changes. (Gilardini et al., 2016; Belcaro et al., 2013)
Another formulation in a coated tablet format (Monoselect Camellia) containing highly bioavailable green tea extract was useful as an adjunct to a low-calorie diet to treat obesity. (Di Pierro et al., 2009)
The most well-known chemical constituent of tea is caffeine, which is stimulating. Caffeine in tea is approximately 4 percent in dry weight. Tannin is the other principal constituent of tea.
Caffeine, theobromine, and theophylline are polyphenols belonging to the phenolic group of compounds. The major flavonols in tea are- catechin, epicatechin, epicatechin gallate, gallocatechin, epigallocatechin, and epigallocatechin gallate. Epigallocatechin gallate is the most active of these catechins. Another compound – L-theanine, is an amino acid found in tea. Theanine in green tea plays a role in reducing stress. Oxidized catechins (theaflavins in black tea) reduce cholesterol levels in the blood.
Tea decreases lipid and carbohydrate absorption, increases lipid metabolism, inhibits de novo metabolic production of fat, and increases carbohydrate utilization. (Grove et al., 2010) Green tea intake is associated with increased weight loss due to diet-induced heat generation attributed to the catechin epigallocatechin gallate. (Shixian et al., 2006)
High caffeine intake was associated with weight loss through heat and fat oxidation and suppressed leptin in women. (Leptin is a molecule that triggers a signal of satiation to the brain). The green tea-caffeine mixture improved weight management in habitually low caffeine consumers, partly through heat generation and fat oxidation. (Westertep-Plantenga et al., 2005)