Fad diets: You need to know the truth

Cut this out, try this, eat more of this, drink less of this, don’t do that, do this instead. There are so many diets out there claiming to give that illusive beach body we are all looking for. While some may offer the results you are looking for, can this weight loss and improvement in health be sustainable? Or are we setting ourselves up for failure when it comes to out waistlines and possibly ill-health?

Longevity has taken a look at 4 popular diets and examined the science and research, or lack thereof, behind each of them to ensure that you are looking after your health when considering an approach to weight loss.

1. The blood type diet:

The Blood Type diet, which was created by naturopath Peter J. D’Adamo, claims that the food we eat reacts chemically with our blood type and that we should tailor our diet according to what our blood type is. D’Adamo suggests the following diets for each blood type:

– Type O blood – should look at a high-protein diet heavy on lean meat, poultry, fish and vegetables which is light on grains, beans and dairy.

– Type A blood – should look a meat-free diet based on fruits, vegetables, beans, legumes and whole grains as the base of the diet and should have a focus on organic and fresh foods as those with type A blood have weaker immune systems.

– Type B blood – should avoid corn, wheat, buckwheat, lentils, tomatoes, peanuts and sesame seeds. He also says that chicken can be problematic. He encourages eating green vegetables, eggs, certain meats and low-fat dairy.

– Type AB blood – should focus on including tofu, seafood, dairy and green vegetables. He says that people with AB blood tend to have low stomach acid so should avoid alcohol as well as smoked and cured meats.

The facts:

According to Melissa Kelly a registered dietitian, and a recognised expert in the field of evidence-based nutrition, “the blood group diet shows results of weight loss for the mere fact that every blood group will change their dietary intake and by eliminating certain foods, like wheat, dairy or meat, you will see changes in your weight and health.” A study done by Stellenbosch University showed that when the amount of energy consumed by people following a low carbohydrate and/or balanced diet, there was no difference in weight loss compared to that of the blood group diet, as it merely comes down to cutting down the amount of energy.

2. The Mediterranean diet: 

The Mediterranean diet is a heart-healthy diet plan which focuses on incorporating fruits, vegetables, beans, legumes, seeds, nuts, herbs and spices and olive oil into your diet as the bottom of your pyramid of eating.  The diet, which originated in Greece where an average of six or more servings a day of antioxidant rich fruits and vegetables were served, is one that also focuses on grains, typically whole grains. The focus of the Mediterranean diet isn’t on limiting total fat consumption, but rather on choosing healthier types of fat. The Mediterranean diet discourages saturated fats and trans fats, both of which contribute to heart disease and other non-communicable disease.

The facts:

Recent research published by The Mayo Clinic, has shown that the traditional Mediterranean diet reduces the risk of heart disease by a good margin. In fact, an analysis of more than 1.5 million healthy adults demonstrated that following a Mediterranean way of eating was associated with a reduced risk of death from heart disease and cancer, as well as a reduced incidence of Parkinson’s and Alzheimer’s diseases, possibly due to the inclusion of healthy omega fats. The Dietary Guidelines for Americans recommends the Mediterranean diet as an eating plan that can help promote health and prevent disease. And the Mediterranean diet is one your whole family can follow for good health.

A newer study published in the Clinical Journal of the American Society of Nephrology has also shown that the Mediterranean Diet could help reverse Metabolic Syndrome. People who maintained a version of the Mediterranean diet had a 50% lower risk of developing chronic kidney disease and a 42% lower risk of rapid kidney function decline, according to the study. Over about seven years, researchers scored 900 participants’ diets on a scale based on how closely their eating habits resembled the Mediterranean diet. They found that every one-point increase in Mediterranean diet score was linked to a 17% decrease in their likelihood of developing chronic kidney disease—a disease that afflicts around 20 million Americans.

3. Low-carb, high fat (LCHF) diet:

This diet has been the focus of a lot of media attention and medical debate in the past few months, with dietitians and nutrition experts standing their ground with regards to the unsustainable nature of this type of eating plan. Also known as Banting, this diet is highly promoted by Professor Tim Noakes, who has advocated a drastic decrease in carbohydrate intake and an increase in the amount of fat in the diet.

The facts:

Medical specialists are outspoken against this form of extreme dietary limitation, saying that a healthy diet is one that promotes the ability to find a balance between the intake of protein, fats and carbohydrates. Stellenbosch University participated in a study published in the international PLOS ONE journal, which reviewed the result of 19 international scientific trials.

As part of these trials, about 3200 participants were placed either on low-carbohydrate or balanced weight loss diets. Studies lasted between three months and two years, and measured the diets’ impacts on risk factors related to heart disease, diabetes and cancer.

The study showed that fad banting diets that drastically restricted carbohydrate intake in favour of fats resulted in weight loss by restricting caloric intake – not by lowering the amount of carbohydrates consumed.
The systematic review which was also issued by the Association for Dietetics in South Africa, Chronic Disease Initiative for Africa, Heart and Stroke Foundation South Africa, the Nutrition Society of South Africa and Professional Board for Dietetics and Nutrition of the HPCSA, included overweight and obese people with and without diabetes. The results showed that little or no difference was detected for known heart disease and diabetes risk factors over 2 years. This study found that the reduction of energy, not necessarily only found in carbohydrates, lead to an increase in weight loss over time. It also showed that drastically cutting back carbohydrate intake will give you short term success when it comes to weight loss but that this might not be effective in keeping that weight off.

“This study shows that when the amount of energy consumed by people following the low carbohydrate and balanced diets was similar, there was no difference in weight loss,” says lead researcher, Dr Celeste Naude, from the Centre for Evidence-based Health Care at SU’s Faculty of Medicine and Health Sciences.

Based on these findings the Heart and Stroke Foundation South Africa, the Association for Dietetics in South Africa and other health groups are warning the public about the possible health risks associated with banting. “Decades of research have shown the balanced diet to be safe and healthy in the long term, and along with a healthy lifestyle, is associated with a lower risk of heart disease, stroke, diabetes and certain cancers,” says Heart and Stroke Foundation South Africa CEO Dr Vash Munghal-Singh. “We do not have similar proof that a low-carbohydrate diet is safe and healthy in the long term, and some studies already point towards an increased risk of heart disease and death with low carbohydrate diets.”

“Chronic diseases like heart disease, stroke, cancer and diabetes develop over many years of exposure to risk factors,” she tells Health-e News. “The follow-up of the trials included in the review is no longer than two years, which is too short to provide an adequate picture of the long term risk of following a low carbohydrate diet.”

“Based on the current evidence we cannot recommend a low-carbohydrate diet to the public,” Munghal-Singh concludes.

Another one of the fundamental results that this review showed was that weight loss in itself improves risk factors of heart disease and diabetes and that this is not simply due to a cut back in the amount of carbs you eat, therefore debunking the notion that the exclusion of carbohydrates will result in sustainable improved health and weight loss.

“The initial fast weight loss associated with Banting can drive motivation but studies have shown that it may result in more weight loss and better improvements in blood lipid and glucose levels when compared to 6 months of conventional dieting, however when compared at 12 and 24 months these differences fall away,” says Celynn Erasmus, a registered dietitian in South Africa. She also explains that this type of dieting, where you severely cut your carbohydrate intake, can result in ketosis.

4. Paleo diet:

The Paleo diet, which is also known as the caveman diet, refers to the simplest form of eating there is. Back in the day, cavemen had to eat whatever they could hunt or collect from their surroundings and this is the basis of the Paleo diet. The diet looks to incorporate lean proteins, fruits and vegetables and healthy fats from nuts, seeds, avocados, olive oil and fish oil. The lean proteins support strong muscles, healthy bones and optimal immune function whereas the fruits and vegetables are rich in antioxidants, vitamins, minerals and phytonutrients.

The facts:

Research has shown that one of the greatest deviations away from our ancestral diet is the amounts and types of fat found in modern grain feed animals vs. the amounts and types of fats found in grass fed or wild meat, fowl and fish, as it was back in the day. The research has shown that wild meat is remarkably lean, and has relatively low amounts of saturated fats, while supplying significant amounts of beneficial omega-3 fats, such as EPA and DHA. In this paper Professor Cordain and his team analyze the complete fatty acid profile from several species of wild deer and elk. Scientific and epidemiological studies show that diets, like the Paleo diet, that are rich in Monounsaturated and Omega-3 fats dramatically reduce the instances of obesity, cancer, diabetes, heart disease and cognitive decline. However, with it being extremely difficult, and often expensive, to get your hands on hormone free, grass fed meat and organic fruit and vegetables the Paleo diet is one that would be difficult to implement over a long period of time, making it not very sustainable.

At the end of the day, we are not here to bash any diets, or the people who advocate them, but rather we are here to promote choices that are going to be beneficial to your overall health and wellness in the long run.

You need to make sure you make choices based on what will suit your lifestyle, what will promote improved health in the long run as well as what is going to lead to sustainable weight loss and health improvements. Fad diets, which Melissa Kelly, refers to as any diet that looks to cut out a certain food group, are not going to promote sustainable weight loss and improved health. We need to be able to find a balance between the food groups that make up a diet as well as to include the good, healthy options of each.