Tag Archives: weight loss

Science or Snake Oil: do skinny teas boost weight loss?

The Conversation

File 20171212 9383 1e2tlrz.jpg?ixlib=rb 1.1
‘Skinny teas’ might not have any properties to help you lose weight, but they might remind you you’re on a diet. from http://www.shutterstock.com

Clare Collins, University of Newcastle

Weight loss teas are becoming common, with advertisements claiming dramatic results often appearing online. Do the big promises match the results, or do they only match the price tag?

A search of the medical research database pubmed found there are no studies specifically on the use of “slimming teas” for weight loss, but there are studies on green and black tea.

One review of five research trials compared changes in body weight in more than 300 adults at high risk of type 2 diabetes and heart disease. They gave people either green tea, a fermented tea called Puehr or tea extracts and compared the weight change to people who were given either placebo (non-active) tea extracts or no tea at all.

They found that in the group of people who had the most risk factors for type 2 diabetes and heart disease, and who also ate more healthy foods and exercised more, those having the tea or tea extracts had a weight reduction of about 4kg. Interestingly, in the group who were not given healthy lifestyle advice and who did not have many risk factors, the average weight loss was only about 350 grams.


Read more – Health Check: six tips for losing weight without fad diets


These results suggest most of the weight loss was due to the impact of following the healthy lifestyle advice, and that there may have been some extra motivation to stick to that advice among those who were at high risk of other health problems.

An analysis of six studies examined the effect of tea mixtures that contain added catechins (a chemical compound found in tea that have a bitter flavour) and caffeine or caffeine-only supplements on the body’s energy expenditure. They found both significantly increased the amount of energy the body burns over the day, by approximately 5%. That may not sound like much, but it’s equivalent to about 430 kilojoules per day, or the kilojoules in a medium banana.

In another review of the effects of green tea and added tea extracts on body weight regulation, consuming green tea with the tea extract added was associated with a 1.3 kilogram greater weight loss compared to not consuming them over about three months.

Slimming teas can have herbal tea components, herbal extracts or other additives mixed in with the tea. There’s limited good quality research on the effectiveness of these compounds, although some have been around for decades. But there has been a case report of heart failure triggered from using a herbal weight loss tea that was thought to have illegally contained weight loss drugs known to cause heart problems, so caution must be exercised.

It’s important to look at what’s in the tea you’re drinking.
from www.shutterstock.com

Read more – Health Check: what’s the best diet for weight loss?


Botanical compounds that might be added to slimming tea include the following, so check the label:

  1. Senna, a laxative used to treat constipation;
  2. Valerian root, which has some evidence that it may improve sleep quality;
  3. Roots of the burdock plant, which are thought to contain chemicals that act as a diuretic (and increase urine production);
  4. Yerba mate, a plant common in South America. The leaves are used to make a drink high in polyphenols, a group of compounds found in plants that help the body defend itself against disease. Yerba mate also contains caffeine, so it has a stimulatory effect similar to coffee. A recent review suggests it may be helpful in lowering blood cholesterol levels;
  5. Dandelion leaf contains chemicals thought to have a diuretic effect, but there’s no strong evidence to support this effect;
  6. Celery seed can be used as a spice or flavouring, the active ingredient apiole has been thought to have anti-cancer effects (in mice); and
  7. Calendula flowers are edible and a review of their medicinal use through out history found potential wound healing and anti-swelling properties.

As long as you do not have any sensitivities or a chemical intolerance to slimming tea components, they might have a powerful placebo effect and act as a timely reminder to stick to a weight loss diet. Interestingly, the placebo effect is supported by evidence.

While the price of slimming teas vary, check the small print for disclaimers before you part with your money. They might read something like:

For maximum health benefits this product should be consumed in conjunction with a low kilojoule diet and daily exercise, individual results may vary.

The ConversationThink about whether you get better value from A$30+ dollars worth of weight loss tea or from buying a regular box of green or black tea, and spending the price difference on buying more fruits and vegetables. The research evidence indicates higher intakes of fruit and vegetables are associated with a lower risk of weight gain, heart disease, type 2 diabetes, some specific types of cancer and age-related health decline.

Clare Collins, Professor in Nutrition and Dietetics, University of Newcastle

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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Eat food, not nutrients: why healthy diets need a broad approach

The Conversation

Rosemary Stanton, UNSW Australia

There seems to be a shortening gap between studies about diet, nutrition and health. And each starts another conversation about trans vs saturated vs polyunsaturated fats, or this diet vs that, or, as is today’s case, fats vs carbohydrates.

In a paper published today in the journal Cell Metabolism, researchers found that when 30% of a day’s kilojoules were restricted by cutting fats (diets with a higher intake of carbohydrates), participants in their study lost more body fat compared to when the same amount of energy was restricted by cutting carbs (diets with a higher intake of fat).

This study used a type of meticulous metabolic research, which is expensive and unsuited to lengthy periods, but valuable for exploring the physiology of reducing equal dietary contributions from fat or carbohydrate. But like much dietary analysis, it may be shining a light on the wrong issues altogether.

The good, the bad and the ugly

The most important aspect of any diet is that it should be practical and healthy enough to follow for the rest of your life. There’s no magic bullet for weight loss. While some people claim they find it easier to cut out foods high in carbohydrates, others find it easier to avoid high-fat foods.

If you need to lose weight, cutting down is what helps. But few people can stick to any extreme diet for life, so what you substitute is just as important as what you cut out – especially for long-term health.

Choices based only on macronutrients (foods required in large amounts in the diet, such as fats, carbohydrates and protein) miss important aspects of many foods and open the diet to imbalance. Carbohydrate foods, for instance, include nutritionally worthy choices – such as legumes, wholegrains, fruits, milk and yoghurt – but also a huge range of items high in sugar or refined starches with little or no nutritional attributes. “Cutting carbs” doesn’t distinguish between the good and bad foods in this category.

This may not be the best way to get your daily ration of fruit. Adrian Scottow/Flickr, CC BY-SA

The same thing happens with fats. Sources of unsaturated fat – such as nuts, seeds, avocado or extra virgin olive oil – have proven health benefits. But there’s no evidence for any benefits of lard, dripping, cream, fast foods or any of the fatty snack foods that account for much of our saturated fat intake. And no long-term study shows sustained weight loss or other health benefits from a diet high in saturated fats.

Some foods are more even problematic. Most fast foods are high in saturated fat and salt, and lack dietary fibre. And they’re not only largely devoid of vegetables (apart from the odd gherkin), but often displace meals that would have contained vegetables.

Biscuits, cakes, pastries, many desserts and confectionery provide a double whammy with high levels of unhealthy fats as well as sugar and refined starches. Make that a triple whammy because most lack any nutritional virtue as well.

From bad to worse

Assumptions based on macronutrients are simply too gross to be meaningful. This is apparent in so-called meta-analyses based on a mixture of cohort and case-control studies that use different methods and time frames relating to what people eat, and fail to report all aspects of the diet.

One review, for instance, claimed that saturated fat was unrelated to cardiovascular disease. But it ignored the adverse impacts of the foods that had replaced saturated fats and provided no information about the foods that provided saturated fat in the first instance.

Worse still, such analyses are prone to many errors. A long check of every reference used in that meta-analysis showed that the conclusion would have differed if 25 studies had either not been omitted or had been reported correctly (sadly, it’s paywalled).

Another recent review also failed to show any clear association between higher saturated fat intake and all-cause mortality, heart disease, ischaemic stroke or type 2 diabetes, although the authors were unable to confidently rule out increased risk for heart disease deaths. They also noted that the certainty of associations between saturated fat and all outcomes was “very low”, which means we don’t yet understand the association between saturated fats and disease.

Not all dairy products are created equal. Samir Rahamtalla/Flickr, CC BY-NC-ND

Hopefully, further research will distinguish between food sources of saturated fats; they are not all equal. There’s already good evidence that processed meats can have more deleterious effects than fresh meat. And that fermented dairy products, such as yoghurt and cheese, may also have health benefits and are distinctly different for heart health risk compared to butter.

Swapping saturated fat for sugar or refined starches is worse than useless for preventing cardiovascular disease. But please direct criticism of foods where fat has been replaced by sugar at the food industry. Dietary guidelines have always recommended limiting sugar as well as saturated fat.

A sorry state of affairs

Unfortunately, in most developed countries, sugar consumption remains high while intakes of vegetables, legumes, fruits, nuts and wholegrains are low. And while macronutrient intakes in countries such as Australia may look fine (31% of energy from fat and 44% from carbs), problems remain with the kinds and amounts of foods we consume.

Junk food and drinks were once consumed only as an occasional treat, but they now contribute significant portions of both adult and children’s diets – in Australia, 35% of adults’ and 41% of childrens’ energy intake. Confectionery and starchy, fatty, savoury snack food intake have also increased significantly.

It really is time to focus on foods instead of wasting time on macronutrients. Australia’s Dietary Guidelines have made this change, as has the new simple Swedish equivalent, which emphasises sustainable choices. Norway and 20 European countries also take a food focus and the number one point in Brazil’s enlightened guidelines is that diet is more than the intake of nutrients.

Consider the dozens of studies on Mediterranean diets, including randomised trials, where the fat and carbohydrate content vary but the health value depends on particular foods: extra virgin olive oil, nuts, vegetables, fruits, grains and legumes and a low intake of highly processed products. The take-home message from these is that we need to stop fussing over macronutrients and think about foods.

The ConversationRosemary Stanton is Nutritionist & Visiting Fellow at UNSW Australia.

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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