Green Tea – Weight Loss Benefits and Side Effects

Green Tea

What is Green Tea?

Green Tea

Made from the leaves of Camellia sinensis, often flavored for improved taste.

Taste: Slightly bitter

Function: Aids in weight loss and maintaining a healthy body

Supplement usage example: Fat burners like Instant Knockout, Trimtone, PhenGold, etc.

Similar fat-burning ingredients:
Green coffee, guarana, yerba mate, etc.

The origin of green tea dates back to more than 4,000 years and has its roots in China. The first green tea was brewed in 2737 BC according to the legend.

Green tea is packed with polyphenols, also referred to as catechins. The concentration of catechins in green tea is higher than in black or oolong tea. Catechins are the bioactive ingredients of green tea which promote weight loss through their extensive functions.

Green tea also provides reasonable amounts of caffeine – not as much as coffee but significant enough to make a difference. Caffeine acts as a stimulant and improves your performance during exercise and aids in burning fat.

Benefits of Green Tea for Weight Loss

According to the University of Maryland Medical Center, you need to drink 2-3 cups of green tea daily for weight loss. This will provide you with the adequate amount of caffeine and polyphenols which will aid in the purpose. Depending on the type of technique you use to brew your tea, a cup of green tea has about 10 to 60 mgs of caffeine and 120 to 230 mgs of catechins.

The catechins in green tea help in:

  • Preventing accumulation of body fat and also inhibit the absorption of fat from meals, increasing the excretion of fats
  • Increasing body temperature which enables you to burn more calories
  • Mobilization of fat from the fat cells to be used as fuel
  • Boosting the metabolic rate

How Does It Work?

The stem, leaf and leaf bud are the useful parts of green tea. By steaming the fresh leaves at high temperature, the important molecules of polyphenols are retained in their useable form. The functions of the three green tea components can be summarized as under:


They help in:

  • Prevention of swelling and inflammation
  • Reduce degeneration of joints
  • Fight papilloma virus infections


The caffeine in green tea comprises about 2% to 4% of its nutrient value. Caffeine:

  • Stimulates the nervous system, muscles and the heart by releasing chemicals known as neurotransmitters
  • Increases the urine output


The antioxidants present in green tea help in protecting the heart and blood vessels.

The Correct Way to Brew Green Tea

how to brew green tea

Just so you know, there is a correct and wrong way of brewing green tea. Boiling water is harmful for the antioxidants and polyphenols, which can damage them and reduce their function. When brewing, make sure to use hot rather than boiling hot water to reap the complete benefits of green tea.

Other Benefits

Weight loss is only one of the abundant benefits of green tea. Other benefits include:

  • Improves the overall health of your body
  • Improvement of brain function – making you smarter!
  • Improvement in physical performance by mobilization of fat tissues
  • May lower the risk of various kinds of cancer (ongoing research)
  • May lower the risk of cardiovascular disease, type 2 diabetes, and Alzheimer’s and Parkinson’s diseases in old age
  • Improvement in dental health by killing bacteria and reducing infection

Clinical Studies

Many studies have been performed which add to the function of green tea as an effective brew for weight loss. Some of them are outlined as under:

  • Green tea clinical studies research findingsEpigallocatechin gallate (EGCG) is the main antioxidant which inhibits the enzyme that leads to the increase in norepinephrin levels. Norephinephrine signals the fat cells to break down fat. The high levels of this hormone increase the breakdown of fat. So, EGCG and caffeine may have a synergistic effect.
  • In a study, 17% more fat was burned by men who took green tea extract along with exercise as compared to men who didn’t take green tea.
  • Another study has proven that the effects of green tea for burning fat are applicable for both during rest and exercise.

Side Effects

Green tea taken with proper guidance has almost no side effects, provided that you:

  • Do not take green tea early in the morning on an empty stomach – because the caffeine can lead to dehydration which stimulates the release of gastric acid, which might lead to an upset stomach or even ulcer.
  • Do not take green tea with meals because it will reduce the absorption of vitamin B1 (thiamine). Deficiency of thiamine causes a condition called beriberi.
  • Do not take with calcium or iron rich foods because it reduces the absorption of calcium and iron derived from plants.

Taking too much of green tea, such as more than five cups a day can cause multiple side effects which can be very mild or serious depending on your consumption:

  • Nausea
  • Headache
  • Irritability
  • Heartburn
  • Dizziness
  • Diarrhoea
  • Sleep problems
  • Irregular heartbeat


serving green tea

Though green tea has proven effects for weight loss, it must not be ignored that noticeable effects occur when green tea is used to supplement burning fat during exercise as well as following a healthy diet, and counting your calories. There is no magic potion out there to take away your extra pounds, but given the great health effects of green tea, adding it in your daily diet will surely help you in maintaining a fit and healthy body.

Source of Study:

  • International Journal of Obesity
  • Journal of Health Science, 51(2) 233-236 (2005)
  • US National Library of Medicine – National Institutes of Health