10 common diet myths debunked by science

“Dietary advice does not merely need a review; it should not have been introduced.”

This is the arresting conclusion made in a new review published in BMJ’s Open Heart journal.

In this instance, the researchers are referring specifically to the fat recommendations in national dietary guidelines.

Nutritional science is a dynamic field and knowledge is growing quickly, debunking long-held beliefs. Beliefs like margarine is better than butter or that fat makes you fat.

Here are 10 common nutritional beliefs that have been debunked by science.

1. Saturated fat is bad

This myth started in the 1970s with the flawed Seven Countries study, which looked at the correlation between saturated fat intake and heart disease among 12,763 men from seven different countries.

The study failed to consider whether the men smoked, did exercise or consumed sugar, among other factors.

Saturated fat, as the new BMJ study has found, is not bad for weight or heart health.

In fact, it can even be good for us – if it’s coming from healthy sources like organic eggs, coconut oil, butter and range-raised, grass-fed meat instead of salami and fast food.

“The truth is, saturated fats from animal and vegetable sources provide the building blocks for cell membranes and a variety of hormones and hormone-like substances, without which your body cannot function optimally,” says Dr Joseph Mercola.

“Any dietitian working with clients for weight loss or to improve blood lipids knows it is the fat balance in the diet that is crucial, not just the saturated fat intake,” adds dietitian Susie Burrell. “Anything is bad if we have too much of it, but 15-20g saturated fat each day via dairy or meat and a balanced diet is no issue.”

Bottom line: As part of a balanced diet, saturated fat is not bad. In fact, when it comes from the right sources and is eaten in moderation, it can be beneficial to our health. “Dietitians are now recommending that people focus on whole foods as opposed to purely on nutrients,” says accredited practising dietitian from Nutrition Plus Melanie McGrice.

2.  A low-fat diet is better for health

This comes from the same school of thought that labelled fat bad. It has, thankfully been debunked on multiple levels.

A low-fat eating pattern does not cut health risks of cancer or heart disease, studies have shown, and it does not lead togreater weight loss than a high-fat diet.

“Low-fat processed foods tend to contain refined carbohydrates and added sugars – in general processed foods are not a good choice,” Burrell says.

Bottom line: It’s still a matter of moderation, but this myth needs skimming. The Dietitians Association of Australia suggests about 70 grams of fat per adult per day. To put it in perspective, an avocado has about 15 grams of fat. “In recent years we have learnt how important a small amount of fat is for part of a healthy diet – even for those who want to lose body fat,” McGrice says.

3. Salt is the devil

A new study, conducted over 10 years, found that sodium intake was not associated with higher death rates, cardiovascular disease or heart failure.

“There is a need for stronger evidence, preferably from rigorous controlled trials testing additional thresholds for sodium intake, before applying a policy of further sodium restriction to older adults beyond the current recommendation for the general adult population (2300 mg/dl),” the authors said.

In fact a separate study of more than 100,000 found that a diet too low in salt can have negative health implications.

“Research in nutragenetics is now showing us that some people are more sensitive to salt than others, so salt’s impact on your health may be affected by your DNA,” note McGrice.

Bottom line: For healthy individuals, without blood pressure or heart issues, a moderate amount of salt isn’t bad. Instead of slavishly counting milligrams, one idea is to eat real (not processed salt-packed foods), add salt where necessary for flavour and leave it at that. “There are worse things going on with Australian’s diet than salt – if you cut back on fast and processed foods, you will automatically cut back on salt,” Burrell points out.

4. Sugar is the dietary devil with its empty kilojoules

OK, sugar sure looks and tastes a treat. But, it can be very badly behaved. If we eat too much of it, that is.

It is not just the way it delivers empty calories, completely devoid of nutrition. It is the way it messes with your insulin, making you want to go back for more. And more.

It’s the way it can cause metabolic problems, diabetes and even cardiovascular disease.

We currently consume too much sugar and there is no doubt we need to dabble less in the sugar dance.

It’s also more than just empty kilojoules

BUT, a little sugar is not the dietary devil, as some food activists say.

“Added sugars via soft drink, lollies, snack foods offer little nutritionally and should be kept to a minimum in the diet,” Burrell advises. “A small amount of natural sugars in fruit and dairy is no cause for concern.”

Bottom line: For healthy, active people who eat a well-balanced diet, a small amount of sugar is sweet. “If you’re undertaking plenty of physical activity, and brushing your teeth regularly, there’s no harm in having some jam on your toast or a little chocolate syrup in a glass of milk to add flavour and variety to your diet,” McGrice says.

5. Eggs are evil 

“Eggs are one of the most nutrient dense natural foods available,” says Burrell.

Recent research has debunked the idea that eggs are bad for heart health and cholesterol in healthy individuals. In fact, eggs are rich in iodine, for making thyroid hormones, and phosphorus, which is essential for healthy bones and teeth. They are also packed with vitamins A, B, E and D.

As well as this, eggs activate serotonin, the happy hormone.

“Eggs have been recommended as a great source of nutrition by the Australian Dietary Guidelines for over a decade now,” McGrice points out.

Bottom line: Eggs are good for body and mind, so get cracking, preferably with free-range or organic eggs, which studies have shown to be more nutritious.

6. Multiple small meals beats three square meals

Despite a recent trend towards small meals spread evenly throughout the day to fuel the metabolism, there is no solid evidence that this happens.

Rather, research has revealed that it is the total amount of food eaten in a day that makes the difference to appetite, fat loss and metabolism. This is regardless of whether you’re consuming three square meals or six small ones.

“Whether you should eat three meals or include snacks in between largely depends upon your routine and lifestyle,” McGrice says.

“Many Aussies snack too much with 6-8 eating occasions a day,” adds Burrell. “Three to four suit most people – breakfast, lunch, mid afternoon and dinner.”

Bottom line: Watch your quantities however you consume them and stick with what works for you, but it is not true that eating more frequently will burn more kilojoules over the course of the day.

7. Low fat dairy is better for health and weight loss

Many health guidelines recommend low fat dairy to minimise kilojoule intake. Additionally, full fat dairy has been slandered by the saturated fat equates to a greater risk of heart disease and obesity.

Interestingly, studies have shown an inverse association with full fat dairy and obesity risk.

As well as this, overall intake of dairy products was not associated with early death. The conclusion of one long-term study: “A possible beneficial association between intake of full-fat dairy and cardiovascular mortality needs further assessment and confirmation.”

Adds McGrice: “The difference in fat between full cream milk versus low fat milk is only 2% so doesn’t amount to a very big difference in kilojoules anyway unless you’re drinking litres of milk every day, the key message is to ensure that you’re including three serves of dairy or dairy alternatives in your diet each day.”

Bottom line: Full fat dairy has been linked with a reduced risk of obesity and possibly even heart disease. As with anything the key is easy does it. “If the rest of the diet is low in processed and fast foods, a small amount of full cream dairy can be a part of a balanced diet,” Burrell says.

8. Cooking with olive oil is bad

This rumour has been doing the mainstream rounds in recent years. Olive oil has been called the healthiest fat on the planet. It runs its liquid gold goodness right through the Mediterranean diet, is abundant in antioxidants and improves risk factors related to heart disease, cholesterol and diabetes.

But, some researchers have said that olive oil burn at low temperatures compared to other types (like coconut oil), and when oil is overheated, it produces toxic chemicals called lipid peroxides.

Various other studies however have found this to be untrue and found heated olive oil to be more stable than oils like sunflower or canola.

“Deep frying in olive oil will destroy the oil but olive oil still offers the health benefit of acting as a rich source of antioxidants when used in cooking at medium temperatures,” Burrell explains.

“Variety is the spice of life and I think that it’s a great idea to vary the types of oils that you use to create different flavours in your meals,” McGrice suggests.

Bottom line: Olive oil can tolerate heat and is OK to cook with as well as being wonderful in salads… and pretty much everything else.

9. Skipping breakfast is a terrible idea

Breakfast isn’t necessarily the most important meal of the day, for weight-loss at least, recent research has revealed.

One study found that while eating breakfast resulted in greater initial weight loss among participants, those who tended towards eating later instead were better at maintaining fat-free mass, which impacts metabolism.

“What time you have your first meal of the day really should come down to your lifestyle and what you eat for your first meal,” McGrice advises. “If your first meal is a doughnut at 11am, then maybe you should be considering eating breakfast.”

Adds Burrell: “Eating the first meal of the day as early as possible helps to boost metabolic rate.”

Bottom line: Breakfast is known to have a positive impact on cognition, but skipping it won’t necessarily slow your metabolism. Start the day how it feels natural for you  and eat when you’re hungry.

10. Fasting slows your metabolism and increases cortisol

Dr Michael Mosley popularised the idea of intermittent fasting. But, rumours persist that going without food will slow your metabolism.

This is not true, so long as the fasts are for short periods, research has revealed.

“New research suggests that occasional fasting may even boost metabolism, if done in the right way,” says Burrell.

One recent study found beneficial effects of intermittent fasting on glucose regulation and cardiovascular function. Other studies have found that overnight fasting (after dinner waiting 12 hours to eat breakfast) can improve blood sugar and metabolism levels, help fight high cholesterol, diabetes and obesity.

“Your metabolism slows when your body runs out of fuel and has to start breaking down muscle mass, but your body should have enough glycogen stores to last a few days before this occurs,” McGrice says.

Bottom line: Prolonged fasting and severe calorie restriction disturb the endocrine system, but intermittent fasting can have positive effects on our health and waistlines.

ketogenic and Paleo diets aid weight loss

Dietary fat has long been blamed for causing obesity, but experts now say high-fat, low carb diets such as the Paleo, Atkins and ketogenic plans beat low-fat diets for weight loss because eating fat can make you skinny.

“The medical establishment got it wrong,” cardiologist Dr. Dennis Goodman told Men’s Journal. “The belief system didn’t pan out.” According to a recent study from the National Institutes of Health, low carb, high-fat diets (LCHF) are significantly more effective for weight loss and preventing heart disease than low-fat diets.

Researchers at Tulane University tracked 148 obese men and women for one year. The subjects ranged in age from 22 to 75 and did not have heart disease or diabetes. The participants were divided into two groups: One group followed a low-carb, high-fat diet that limited their daily carbohydrate consumption to about 40 grams, or 28 percent of their daily calories.

The low-carb dieters consumed about 40 to 43 percent of their daily calories from fat. Their daily menu was similar to the Paleo, ketogenic and Atkins diets, and included eggs, butter, fish, chicken and some red meat and generous portions of healthy fats such as olive oil.

In contrast, the low-fat group consumed 40 to 55 percent of their daily calories from carbohydrates, and their fat intake was limited to less than 30 percent.

Low-Carb Dieters Lost Three Times More Weight Than Low-Fat Group

The results were stunning: The low carb dieters lost about 12 pounds, while the low-fat dieters lost only four pounds even though both groups consumed the same calories. What’s more, the low carbohydrate dieters lost more body fat and scored better than on a test that measured their chances of suffering a heart attack or stroke within the next 10 years.

Physician Dr. Lydia Bazzano, the lead study author, was stunned that a low-carb, high-fat diet could prevent heart disease better than a low fat diet, which has long been prescribed for heart patients.

These results aren’t surprising to Jeff Volek, a leading low-carb researcher and professor at Ohio State University. Volek said high-carb diets cause blood sugar spikes, which fuel inflammation. Inflammation is what causes weight gain, as well as diabetes and cancer.

In contrast, dietary fat has a negligible effect on blood sugar and insulin, which is why eating fat aids weight loss. More importantly, we don’t fuel inflammation, which leads to heart disease, diabetes, Alzheimer’s and cancer, say experts.

While the idea of consuming more fat may sound shocking given the low-fat diet mantra that has dominated the standard American diet (SAD), Volek said we actually evolved to thrive on a low carb, high-fat diet. “For about 98 percent of human history, we’ve been eating low-carb,” Volek told me in an exclusive interview. “We evolved in a state of nutritional ketosis.”

Low carb diets accelerate weight loss by forcing the body to burn fat for fuel in a metabolic state called ketosis, explained obesity expert Dr. Eric Westman, co-author of Keto Clarity. Westman, who has helped hundreds of morbidly obese people lose thousands of pounds on the high-fat Atkins, Paleo and ketogenic diets, said there’s no evidence saturated fat causes heart disease.

“The evidence for that has really disintegrated,” said Dr. Westman, a bariatric surgeon and director of the Duke Lifestyle Medicine Clinic.

The American Heart Association now concedes that refined carbs such as sugar and flour are what cause weight gain and has backed off its longtime stance of recommending low-fat diets to prevent heart attacks. “We no longer think low-fat diets are the answer,” said Dr. Linda Van Horn of the AHA Nutrition Committee.

Many celebrities have hopped on the low-carb bandwagon. Kim Kardashian famously lost 56 pounds on a low-carb ketogenic Atkins diet that limited her daily carb intake to less than 60 grams. Similarly, Tim McGraw lost 40 pounds after adopting the Paleo diet, and is fitter than ever at age 47.

In addition to aiding weight loss, experts say the ketogenic and Paleo diets can prevent Alzheimer’s. Groundbreaking research also suggests the ketogenic diet prevents cancer and starves cancer cells. “The ketogenic diet is a single metabolic approach to a multitude of different diseases,” cancer scientist Dr. Thomas Seyfried of Boston College told me.

Samantha Chang

Paleo diet optimized for weight loss

Chomp, chomp. A new study has revealed that Neanderthals consumed meat and plants, supporting previous theories that their diets featured protein, reported Businessweek on Wednesday. And although there are similarities, the modern Paleo diethas been modified to boost weight loss and health, say experts.

After finding evidence of metabolized plant products in fossilized feces, researchers have more knowledge about precisely what Neanderthals ate, said Ainara Sistiaga, the study’s lead author. And although meat appeared to provide them with most of their fuel, the plant poop proves that veggies “were ingested as part of the diet.”

However, when it comes to percentages, the Neanderthals consumed more meat than greens. That conclusion stems from the discovery that the samples contained high concentrations of broken-down cholesterol similar to modern humans, said Sistiaga.

The poop study provides a new slant, indicating that Neanderthals were omnivorous rather than carnivorous, reported Slate magazine on Wednesday. It’s also one of the most in-depth reports thus far, since other studies were based more on speculation.

Scientists also are intrigued by what happened after they discovered fire, estimated to be two million years ago. Researchers theorize that event resulted in a boost in meat intake. “They probably weren’t prepared for such a high meat intake,” speculates Sistiaga.

So how does this study compare with what modern Paleo dieters eat? They both are low carb diets, and both eliminate dairy and grain. However, Paleo gurus emphasize that caveman dieters can customize the plan to enhance their health.

In an exclusive interview, Robb Wolf, author of “The Paleo Solution: The Original Human Diet,” told me that many people don’t understand the caveman concept approach, which emphasizes quality over quantity. The “calories in, calories out” concept has failed to reverse the rising rates of obesity and its accompanying diseases such as cholesterol.

Insisting that humans need grains and dairy implies that “all food is equal,” says Robb. “The ‘everything in moderation crowd’ (which refers to mainstream medicine and dietetics) has had the last 50 years to preach this message and it has been a complete failure.”

And the Paleo diet today is not limited to meat and veggies. Robb’s research shows that the healthiest approach for dieters is to create a diet “built around fruits, veggies, lean meats, nuts and seeds.”

After numerous studies, Robb feels it is clear that a Paleo diet not only “provides all the nutrients for health, but that the Paleo diet is, calorie for calorie, the most nutritious way one can eat. This position that removing grains and dairy is inherently unhealthy is not based on science.”

Expanding on the omnivorous low carb diet approach, Robb notes that the use of resistant starch in modern Paleo diets highlights “the bigger topic of the human gut biome.” In contrast, consuming refined carbohydrates “appear to feed bacteria in the small intestine leading to a condition aptly named ‘small intestinal bacterial overgrowth.’ This bacterial overgrowth in the small intestine is now being linked to a remarkable number of health issues, from cardiovascular disease to autoimmunity.”

The recognition of the role of fiber has grown, and “it has only been recently that we have understood the mechanism to be that of feeding our beneficial gut flora. A Paleo diet built around fruits, veggies, roots, shoots, tubers nuts and seeds provides an enormous variety of fermentable carbohydrate to keep our gut bacteria healthy,” Robb added.

Taking the omnivorous concept one step further, Paul and Shou-Ching Jaminet have created a modified Paleo diet that includes fish, meat, vegetables, fruit and what they call “safe starches.” The latter includes rice and potatoes, which they emphasize as key to health and weight loss. It’s all detailed in their book “Perfect Health Diet: Regain Health and Lose Weight by Eating the Way You Were Meant to Eat.”

As Robb notes, a significant body of science supports the theory that by avoiding foods toxic to humans, dieters can both shed pounds and avoid disease. The “Perfect Health Diet” avoids grains, legumes, refined sugars and processed oils.

Another advocate of resistant starch is blogger Richard Nikoley. Author of “Free The Animal: Lose Weight & Fat With The Paleo Diet,” he emphasizes that enhancing the traditional Paleo diet in this way can provide benefits ranging from improved sleep to a boost in weight loss.


Two meals a day ‘effective’ to treat type 2 diabetes

Vegetables and fruit

Scientists prescribed two meals a day rich in fruit, vegetables and fibre

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Only eating breakfast and lunch may be more effective at managing type 2 diabetes than eating smaller, more regular meals, scientists say.

Researchers in Prague fed two groups of 27 people the same calorie diet spread over two or six meals a day.

They found volunteers who ate two meals a day lost more weight than those who ate six, and their blood sugar dropped.

Experts said the study supported “existing evidence” that fewer, larger meals were the way forward.

Timing important?

Type 2 diabetes occurs when the body does not produce enough of the hormone insulin, which controls the amount of sugar in the blood, meaning blood sugar levels become too high.

Larger studies over longer periods of time will be needed to back up these findings before we would change advice”

Dr Richard ElliottDiabetes UK

If untreated, it can lead to heart disease and stroke, nerve damage, light-sensitive eyes and kidney disease.

About 2.9 million people in the UK are affected by diabetes, 90% of whom have the type 2 form of the disease.

Current advice in the UK recommends three meals a day, with healthy snacks.

Scientists at the Institute for Clinical and Experimental Medicine in Prague divided a group of 54 volunteers aged 30 to 70 with type 2 diabetes into two groups of 27 people.

Volunteers were then given either a six-meal-a-day diet (A6) for 12 weeks followed by a two-meal day diet (B2), or vice versa.

The study compared two meals with six meals – as the latter accorded with current practice advice in the Czech Republic, researchers said.

Each diet contained on average 1,700 calories a day.

‘Very pleasing’ result

The B2 group ate between 06:00 and 10:00 and then between 12:00 and 16:00, and the A6 group ate their food throughout the day.

Weight loss for the B2 group averaged 1.4kg (3lb) more than A6, and they lost about 4cm (1.5in) more from their waistlines.

Lead scientist Dr Hana Kahleova, at the Institute for Clinical and Experimental Medicine, said the results were “very pleasing”.

She said: “The patients were really afraid they would get hungry in the evening but feelings of hunger were lower as the patients ate until they were satisfied.

“But when they ate six times a day the meals were not leaving them feeling satisfied. It was quite surprising.”

‘Larger studies needed’

Dr Kahleova said the study could apply to people without diabetes who were trying to lose weight.

Dr Richard Elliott, research communications officer at Diabetes UK, said the study added to evidence that eating fewer, larger meals a day could be more effective than smaller, frequent meals at helping people manage their condition.

He added: “However, larger studies over longer periods of time will be needed to back up these findings before we would make changes to the dietary advice given to people with type 2 diabetes.”

Dr Elliot said eating a healthy, balanced diet, being active and maintaining a healthy weight, alongside taking any medication was “vital” to effectively manage the condition.