Green tea benefits: Is the brew as super as its rumoured to be?
Hailed for millennia for its health-boosting properties, green tea boasts benefits galore. From a healthy dose of antioxidants to supporting oral health, blood sugar management and improved cognition, it's as super as super brews get.
And we're sure the rumour that drinking green tea for weight loss, one of those long-standing health food claims that revives every few years, hasn't passed you by.
According to legend, the brew was discovered by the mythical Emperor Shennong in China in 2737 BC. Nowadays, it's a firm favourite of the Hollywood elite. Jennifer Lopez has it before performances, Gwyneth Paltrow has said she won't leave the house without a cup and Jennifer Aniston drinks it throughout the day.
Surprisingly maybe, given the taste, appearance and reputation, green tea originates from the same tea plant as your standard cuppa, the Camellia Sinensis. During the production of black tea, the leaves are allowed to oxidise, which nixes many of the plant's health-boosting properties. Green tea leaves are unoxidised, so it keeps high levels of micronutrients that are packed with antioxidants, known as polyphenols.
These health credentials have seen it be mooted as an aid for everything from headaches to dementia. But, though this brew is undoubtedly good for you, know that while these claims – including that it might help with losing weight – generally have a kernel of truth to them, it's not quite a total health panacea.
So before you start filling your cabinet with green tea bags, here's what to know about green tea and weight loss, and what it can — and can't — do.
Is green tea good for weight loss?
There have been a huge amount of studies investigating the weight loss properties of green tea and generally, in trials ranging between six weeks and six months, they've reported largely positive – although not statistically significant – effects on weight loss and fat composition. It's key to note that in these, participants are generally given green tea supplements, rather than cups to drink.
‘Green tea acts by slightly raising metabolism and preferentially burning fat,’ explains Dr Carrie Ruxton, who has a PhD in Child Nutrition and works with the Tea Advisory Panel. It's believed these effects are due to the high level of catechins, principally EGCG, which is a potent antioxidant and aids weight loss through thermogenesis, a process of heat production in the body.'
It also contains caffeine, which has been proven to encourage lipid oxidation – a.k.a fat burning – and to improve exercise performance.
Does green tea burn belly fat, you ask? Contrary to popular myth, green tea isn't able to target particular areas, though studies have shown it can support weight loss and reduce BMI (body mass index).
'To lose weight and burn fat, your body must first break it down and move it into your bloodstream', explains David Wiener, Training Specialist at Freeletics.
'The compounds in green tea can help aid this process by boosting the effects of some fat-burning hormones, such as norepinephrine (noradrenaline). EGCG is extremely helpful in inhibiting an enzyme that breaks down the hormone norepinephrine, which increases the amount of norepinephrine increases, promoting fat breakdown.'
A 2012 analysis found that green tea did aid weight loss in overweight or obese people, but that this was 'statistically non‐significant' – so, nothing to get too hyped over.
A 2020 meta-analysis of studies carried out on the impact of green tea (again, these trials gave participants green tea supplements, rather than cups to drink) on obese people found that a daily habit lowered body weight by just under 2kg over 12 weeks.
'We suggest that the use of green tea can be combined with a balanced and healthy diet and regular physical exercise in the management of obese patients,' concluded the authors of the analysis. 'This is a modest reduction', says Dr Ruxton, 'which is why green tea works best when combined with healthy eating and sensible portion sizes.’
What are the benefits of green tea?
1. It's antioxidant-packed
The wonder leaves contain catechin, a type of polyphenol and antioxidant that helps prevent cell damage and stave off health conditions.
2. It speeds up metabolism
As we talked about, green tea speeds up metabolism, aiding weight loss as part of a balanced diet.
3. It helps balance blood sugar
It's been proven to benefit people with type 2 diabetes, managing symptoms and lowering the risk of developing it.
4. It might lower the chance of heart disease
Research shows green tea could reduce some of the causes of heart disease, like blood pressure, as well as lowering the chance of heart attacks and strokes.
5. It might help reduce the chance of some cancers
Though its cancer-fighting claims are mostly unsubstantiated, there's some evidence it lowers the risk of some types.
6. It boosts brain health
Containing compounds like caffeine and L-theanine, studies have shown green tea to boost brain power — upping cognition and mood, as well as slowing decline in older age.
7. It's linked to living a longer life
Studies have shown consuming green tea lowers the chance of death from all causes, some by as much as 62%.
How much green tea should I drink?
So, how many green teas a day are recommended? Studies have varied how much is consumed, but it’s generally thought to be between 2-4 cups daily. It’s served without milk or sugar, so it’s calorie-free and can be a good alternative to unhealthy drinks. Much as is often used in trials, you could pop a green pill supplement, rather than drinking brews.
One thing you'll want to keep in mind is that this drink *is* caffeinated. A 230-ml cup of green tea contains between 30 and 50 milligrams of caffeine (FYI doctors recommend having no more than 400mg of caffeine a day).
Which green tea is best for weight loss?
It doesn’t matter which brand you drink, but ‘when choosing which tea is best for you, opt for minimally processed and natural green tea as this will always be the best for your health’, says Wiener.
Avoid bottled green teas, which can contain added sugar or sweeteners.
What about green tea extract for weight loss?
If you don't like a classic cup of green tea, green tea extracts have been proven to have similar benefits. One study on 63 obese adults found a 7.3lb increase in weight loss and 183 more calories burned a day over three months.
When is the best time to drink green tea for weight loss?
There haven't been many studies on specific hours for consumption, so opinions on the prime time vary. The good thing is it means you can just have it when you feel like it; for some that will be the morning, instead of your flat white, but others will find it a handy perk-up in the early afternoon.
‘I would say morning and early afternoon to enable the green tea polyphenols to work alongside your normal activities’, says Dr Ruxton. ‘Exercise and green tea are a powerful combination as both raise metabolic rate and target fat burning.’
As with any caffeinated drinks, try to avoid drinking green tea directly before you go to bed. 'This is because it contains the amino acid L-Theanine which makes you more alert and awake, which aids concentration but disrupts sleep.’ says Wiener.
Is green tea good for working out?
Green tea is proven to be particularly effective for weight loss when combined with exercise. As well as the caffeine improving performance, research shows consumption prior to a workout can help burn 17% more fat. Another showed EGCG can lead to lower levels of body fat in the longer term, though their focus group was obese men.
Wiener explains: 'If you consume green tea before working out, these antioxidant compounds can increase your fat burning during cardio exercise, as well as continuing to burn calories at rest, helping you burn more than you would with exercise alone.'
How should I prepare green tea for weight loss?
‘When making yourself a cup of green tea, make sure to not overheat the water, as excess boiling will damage the catechins’, Wiener recommends. ‘For best results, boil water and then allow it to rest for ten minutes. Then pour it over the tea leaves and let it sit for a couple of minutes before straining the leaves.’
What is the healthiest tea to drink daily?
Green tea takes the crown for overall health benefits as not only is it one of the least processed, but it's full of polyphenols and antioxidants that help boost brain and heart health.
Are there disadvantages to drinking green tea every day?
It's a source of caffeine, so 'if you have caffeine sensitivities, you could experience insomnia, anxiety, irritability, nausea, or upset stomach', says Wiener. 'It is also a diuretic, which makes it ideal for treating and combating fluid retention but, if you drink it too much, it can also be harmful.'
Otherwise, when consumed sensibly, it's natural and healthy.
Speak to your GP before starting any new diets or taking any new supplements, especially if you're on medication. And don't start one solely to lose weight as you can do that more effectively by eating healthily and exercising regularly.
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