Tag Archives: fat

5 common food myths

Myths about common foods that we eat are all over the internet, fitness and health shops and of course the gym. Once these ideas and ‘facts’ take hold they are exceptionally hard to shift.

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Here are the top 5 myths about  the foods we eat.

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#1 : Eggs are full of cholesterol and will lead to a heart attack

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eggs-1I plan on addressing this more fully in a later post because it definitely deserves further attention (I bloody love eggs). Eggs received a bad reputation a number of years ago and unfortunately this has stuck around. Many people mistakenly believe that eating eggs, especially the yolk, has a terrible effect on your cholesterol which increases risk of cardiac/circulatory issues.

It is true that elevated levels of LDL cholesterol is definitely bad for your health but eggs aren’t a significant contributory factor (1,2)

Eggs are a cheap and plentiful source of proteins, fats and an assortment of minerals. If you want to sneak some protein in quickly without spending a lot, eggs are perfect for you.

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#2 : Margarine is healthier than butter

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.I myself am a marge to butter convert. I used to eat margarine, not for any health reason, but because I simply always had. I switched to butter a few years ago after being insulted for eating margarine. ‘what is this bullshit’ people would say when searching for butter in the morning and finding a massive tub of Utterly Butterly or as ALDI calls it, Wonderfly Butterfly ( I love ‘almost’ copyright infringement)

There’s not much difference in calorie content between marge and butter but margarine often contains much higher levels of trans-fats. Eating lots of trans fats is linked to numerous health problems. (3)

Magarine was created as a cheaper and healthier alternative to butter but can actually end up way worse for you in the long run (4). On top of that butter tastes far better!

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#3 : Eat an orange to prevent colds

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I have written  extensively about the role vitamins play in our day to day health and how vitamin supplements, for the average person, are a massive waste of money.

There is a commonly held belief hat vitamin C, found in large amounts in oranges, can prevent or cure common colds.

Neither is true (5).

Vitamin C only seems to play a role in limiting cold duration in specific scenarios involving intensive exercise in cold environments (6)

For a more in depth read about the multivitamin scam take a look here.

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#4 : Go with fat-free alternatives to lose weight

 

fage

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The issue that food manufactures have, especially with more processed foods, is that fat = flavour. If you remove fat from a product in an attempt to create a healthier product then the flavour has to come from somewhere. The answer? Sugar.

This has proved to be a short sighted and potentially health-damaging decision.

Fat has been demonised for decades (mainly due to the power of global corporations that produce sugar-filled products) and the public, and even the government (based on their eating guidelines) believe eating fat is to blame for the obesity epidemic. This has been more heavily scrutinised in recent months following the publishing of a damning report on the topic.

The truth is much more complicated and companies adding sugar to everything in place of fat is nothing but detrimental. In most cases, you would be better off eating the full fat version as the quantity of sugar found in fat-free versions of processed products is preposterous.

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#5 Canned food is less nutritious and ‘healthy’ than fresh

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This all depends on timing. If vegetables and fruit are picked in front of you and you eat them  right there, the fresh stuff will be more nutritious.

However, if we are comparing products in a supermarket the story is reversed. Canning or freezing food essentially fixes it as it was just as it was sealed away – hopefully full of nutrients. In comparison, although visibly fresh, fruit and veg lying around in supermarkets is on a constant downwards nutritional slope from the moment it is picked, all through transport  to the moment you buy and then finally eat it (7).

There is nothing wrong with canned or frozen fruit and veg – in fact, sometimes it might beat the ‘fresh’ version. Taste is another matter!

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Well there you go. Enjoy your canned eggs with butter.

 

-Science Guy

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References

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1) Rong, Ying; Chen, Li; Tingting, Zhu; Yadong, Song; Yu, Miao; Shan, Zhilei; Sands, Amanda; Hu, Frank B; et al. (2013). “Egg consumption and risk of coronary heart disease and stroke: dose-response meta-analysis of prospective cohort studies”. British Medical Journal. 346

2) Hu FB, Stampfer MJ, Rimm EB, et al. (1999). “A prospective study of egg consumption and risk of cardiovascular disease in men and women”. JAMA. 281 (15): 1387–94.

3) K. Hayakawa, Y.Y. Linko, P. Linko, “The role of trans fatty acids in human nutrition,” Journal of Lipid Science and Technology102, 419–425 (2000)

4) Zaloga GP, Harvey KA, Stillwell W, Siddiqui R (2006). “Trans Fatty Acids and Coronary Heart Disease”. Nutrition in Clinical Practice. 21 (5): 505–512.

5) Hemilä H, Chalker E (January 2013). “Vitamin C for preventing and treating the common cold”. Cochrane Database of Systematic Reviews.

6) Douglas RM, Hemilä H (June 2005). “Vitamin C for Preventing and Treating the Common Cold”. PLoS Medicine. 2(6)

7) S.D. Holdsworth (1985) ”Optimisation of thermal processing – A review” Campden Food Preservation Research Association.

The Green Tea Facade

Green tea has been consumed, mainly by Asian nations (having originated in China) for hundreds and hundreds of years. Over the course of history numerous and powerful heath effects have been attributed to frequent consumption of green tea.

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In the modern day, green tea and green tea based products are major staples of health food and fitness shops with much emphasis placed on it’s ‘fat melting’ properties.

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Green tea has also been linked to other extraordinary benefits…

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  • A cure for various cancers
  • Decreases risk of cardiovascular disease
  • Improves glycemic control
  • Reduces ‘bad’ cholesterol
  • A general reduction in risk of death
  • Reduces inflammation
  • Powerful weight loss aid

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These are all extraordinary claims which of course require extraordinary evidence. Luckily a fair amount of research has looked more closely at these proposed benefits…

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Is green tea beneficial to health: What does the science say?

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I’ve gone through the major ‘health benefits’ of green tea and addressed them below. Where possible I’ve used meta-studies to support my arguments. These are large scale reviews of all the available data on the topic and can provide stronger evidence than individual studies alone.

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Cancer: There are a few studies which make suggestive links between consumption of green tea and reduced risk of certain types of cancer in specific populations. A small decrease in esophageal cancer rates amongst the Chinese and slightly lower rates of oral cancers in Asian populations. (1, 2). However it is impossible to control for all variables in these sort of population studies and although overall cancer rates were very slightly lower in green tea drinkers, there are also many many other differences in lifestyle habits that could lead to this outcome.  When all current data is taken together, there is no firm, conclusive evidence that green tea consumption prevents or treats cancer  (3,4).

Search for 'green tea and cancer' and this is one of the first image results. Most of this is wrong. Pseudoscience like this is why I started this website in the first place. Red writing was added by me not some lunatic arguing with himself in an info graphic.
Search for ‘green tea and cancer’ and this is one of the first image results. Most of this is wrong. Pseudoscience like this is why I started this website in the first place. Red writing was added by me not some lunatic arguing with himself in an info graphic.

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Cardiovascular disease: A recent meta-study which compiled a large amount of data on this subject concluded that daily intake of green tea was associated with  a roughly 5% chance reduced risk of death from cardiovascular diseases (this includes things like heart attacks and stroke) (5). A well respected Cochrane review also compiled data from numerous randomised trials a few years previously and reported a small reduction in blood pressure associated with  tea consumption (6). In fitting with these findings, a number of other studies have suggested green tea consumption may also be associated with a reduced risk of stroke (7).

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Blood glucose control: Data here is a little bit messy. Green tea lowered fasting blood glucose in one trial but data generated on fasting insulin levels as well as glycated hemoglobin levels (used to determine longer term average blood glucose) was inconsistent (8,9). Both these references are large scale meta-studies so we can be fairly certain that green tea consumption has no real impact on glycemic control.

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Cholesterol: In this area green tea does appear to have some small but clear benefits. Another Cochrane review (can’t get enough) of longer term trials over 3 months in duration, concluded that green tea consumption lowers total blood cholesterol concentrations in the blood including LDL (low density lipoprotein) cholesterol sometimes called ‘bad cholesterol’ (10).

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LDL - Bad HDL - Goof
LDL – Bad
HDL – Good

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General risk of death: Two separate meta-studies concluded that frequent consumption of green tea resulted in a small reduction in the percentage chance of death from any cause (11,12).

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Inflammation: Green tea consumption is not associated with a significantly lower concentration of c-reactive protein in the blood. C-reactive protein is an acute phase protein from the liver that increases in response to macrophage and T cell activation so is used as a marker of inflammation (13).

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Green tea and pills containing concentrated green tea extract (catechins being the most important component) are  a multi-million dollar market. Although there is some suggestive evidence of small health benefits (see above), green tea is most commonly sold as a weight loss aid.

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But does it actually help with weight loss?

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Green tea is not a weight loss aid

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If you can convince people that your product will help them lose weight then you will make a guaranteed profit. The population is getting fatter and more than ever, people are desperate for a quick fix for weight problems.

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As you’ve guessed – there is no magic pill or easy fix for weight loss. It requires a maintained change to your eating and exercise habits.

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Ridiculous
Ridiculous

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Green tea is described on lots of product labelling as a ‘metabolic booster’ or ‘fat burner’. The main molecule that is often reported to be the ‘fat burner’ is a catechin called  epigallocatechin gallate (EGCG) . So what sort of conclusions are drawn from study’s looking at the ‘fat burning’ properties of green tea?

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Important point to bare in mind: Your average cup of green tea contains about 50-60 mg of EGCG

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One study from 2009 looked directly at the effects of green tea on body composition, measuring things like intra-abdominal fat, waist circumference and total body fat in control subjects and subjects receiving a varying amount of EGCG and caffeine. The group receiving the highest daily dose of EGCG and caffeine saw a clear reduction in all three measurements (14).

.Sounds great right?

.Well not really.

.This group was receiving 900 mg of EGCG a day as well as 200 mg of caffeine on top.

That’s the equivalent of about 18 cups of green tea and 5 cups of coffee...

Neither of which can be described as ‘healthy’ in the long term.

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Another study, published in 2008 approached from a different angle and looked at if green tea could enhance exercise-induced weight loss.

These participants were receiving over 600 mg of EGCG a day. The paper describes a ‘trend towards greater fat mass  loss in the catechin group’  which is another way of saying there was no statistically detectable difference between the groups. (15).

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What about claims that green tea ‘boost or increases metabolism’?

Short answer: It doesn’t.

A number of studies have shown that green tea consumption has no effect at all on the basal metabolic rate of healthy participants (16, 17). Importantly, these studies were measuring basal or resting metabolism . People peddling ‘fat burning’ green tea supplements want you to believe that green tea will simply burn away the extra calories all while you sit on the sofa. Impossible!

A more recent Cochrane meta-study, taking data from 18 separate studies and involving close to 2000 participants concluded that green tea does lead to small weight loss in obese people. However this is described as ‘non-significant and unlikely to be clinically important’. Additionally, green tea has no effect on weight loss maintenance (18).

All strong evidence that Green Tea or Green Tea Extract products are close to useless when it comes to weight loss. 

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Take home message

 

So what have we learned about green tea…

Commonly advertised attributes and the truth side by side:

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  • A cure for various cancers : No
  • Decreases risk of cardiovascular disease: Small reduction 
  • Improves glycemic control: Currently inconclusive
  • Reduces ‘bad’ cholesterol: Small but clear reduction 
  • A general reduction in risk of death: Potentially true but could be explained by many other variables
  • Reduces inflammation: No
  • Powerful weight loss aid: No

 

Although there is some evidence that green tea consumption can have health benefits such as a reduced risk of death from cardiovascular disease and a reduction in cholesterol, relying on supplements for this benefit isn’t necessary. Reducing your intake of trans fats and exercising more will provide you with these benefits plus many more.

In terms of the fat burning potential of green tea, it simply doesn’t exist. 

If you enjoy green tea then by all means enjoy a hot brew every now and then. However if you are forcing yourself to drink green tea for the advertised benefits  or paying through the nose for green tea extract pills then it’s not worth your time or money.

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Thanks for reading,

ScienceGuy

 

 

 

 

References

 

I recommend using Google Scholar for quick access to these studies.

1) Zheng JS, Yang J, Fu YQ, Huang T, Huang YJ, Li D (January 2013). “Effects of green tea, black tea, and coffee consumption on the risk of esophageal cancer: a systematic review and meta-analysis of observational studies”. Nutr Cancer (Systematic Review and Meta-Analysis). 65 (1): 1–16.

2) Wang W, Yang Y, Zhang W, Wu W (April 2014). “Association of tea consumption and the risk of oral cancer: a meta-analysis”. Oral Oncol (Meta-Analysis). 50 (4): 276–81.

3)  Boehm K, Borrelli F, Ernst E, et al. (2009). “Green tea (Camellia sinensis) for the prevention of cancer”. Cochrane Database Syst Rev (Systematic review) (3): CD005004

4) Johnson R, Bryant S, Huntley AL (December 2012). “Green tea and green tea catechin extracts: an overview of the clinical evidence”. Maturitas (Review). 73 (4): 280–7.

5) Tang J, Zheng JS, Fang L, Jin Y, Cai W, Li D (July 2015). “Tea consumption and mortality of all cancers, CVD and all causes: a meta-analysis of eighteen prospective cohort studies”. Br J Nutr (Meta-analysis). 114: 1–11.

6) Zhang C, Qin YY, Wei X, Yu FF, Zhou YH, He J (February 2015). “Tea consumption and risk of cardiovascular outcomes and total mortality: a systematic review and meta-analysis of prospective observational studies”. Eur J Epidemiology(Systematic Review and Meta-Analysis). 30 (2): 103–13.

7)  Khalesi S, Sun J, Buys N, Jamshidi A, Nikbakht-Nasrabadi E, Khosravi-Boroujeni H (September 2014). “Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials”. Eur J Nutr (Systematic Review and Meta-Analysis). 53 (6): 1299–1311

8) Liu K, Zhou R, Wang B, Chen K, Shi LY, Zhu JD, Mi MT (August 2013). “Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials”. Am J Clin Nutr (Meta-Analysis). 98 (2): 340–8.

9) Zheng XX, Xu YL, Li SH, Hui R, Wu YJ, Huang XH (April 2013). “Effects of green tea catechins with or without caffeine on glycemic control in adults: a meta-analysis of randomized controlled trials”. Am J Clin Nutr (Meta-Analysis). 97 (4): 750–62.

10)  Zheng XX, Xu YL, Li SH, Liu XX, Hui R, Huang XH (August 2011). “Green tea intake lowers fasting serum total and LDL cholesterol in adults: a meta-analysis of 14 randomized controlled trials”. Am J Clin Nutr (Meta-Analysis). 94 (2): 601–10.

11)  Tang J, Zheng JS, Fang L, Jin Y, Cai W, Li D (July 2015). “Tea consumption and mortality of all cancers, CVD and all causes: a meta-analysis of eighteen prospective cohort studies”. Br J Nutr (Meta-analysis). 114: 1–11.

12) Zhang C, Qin YY, Wei X, Yu FF, Zhou YH, He J (February 2015). “Tea consumption and risk of cardiovascular outcomes and total mortality: a systematic review and meta-analysis of prospective observational studies“. Eur J Epidemiology(Systematic Review and Meta-Analysis). 30 (2): 103–13

13)  Serban C, Sahebkar A, Antal D, Ursoniu S, Banach M (September 2015). “Effects of supplementation with green tea catechins on plasma C-reactive protein concentrations: A systematic review and meta-analysis of randomized controlled trials”. Nutrition (Systematic review & meta-analysis). 31 (9): 1061–71.

14) Wang et al  (August 2009). ”Effects of catechin enriched green tea on body composition” Obesity 18 (4):773-9

15) Maki et al (December 2008) ”Green tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adults” Journal of Nutrition  139(2):264-70.

16) Lonac et al (August 2010) ”Influence of short-term consumption of caffine-free EGCG supplement on resting metabolism and the thermic effect of feeding”.  Obesity  19(2):298-304.

17) Gregersen et al (May 2009) ”Effect of moderation intakes of different tea catechins and caffeine on acute measures of energy metabolism under sedentary conditions”Journal of Nutrition 102(8):1187-94.

18)  Jurgens et al (December 2012) ”Green tea for weight loss and weight maintenance in overweight or obese adults”.  Cochrane Library