Weight Loss

Posted on Diet, Weight Loss

Danish experiment reveals: You can satisfy your appetite just by looking at pictures of food on your phone.

The results may lead to a new form of treatment for overeating.
The results may lead to a new form of treatment for overeating.

The internet is overflowing with pictures of food: On news sites, social media and the banner ads that pop up everywhere.

Many of the food images are uploaded to sell specific foods. The idea is that the images on Facebook or Instagram will make us yearn for a McDonalds burger, for example. In other words, the image awakens our hunger.

New research from Aarhus University now shows that the images can actually have the opposite effect. At least if we see pictures of the same product repeatedly. 

A number of experiments reveal that we can get a sense of satiety if we see the same image more 30 times. Tjark Andersen, who recently defended his PhD at Department of Food Science at Aarhus University, explains more.

“In our experiments, we showed that when the participants saw the same food picture 30 times, they felt more satiated than before they had seen the picture. The participants who were shown the picture many times also chose a smaller portion than those who had only seen the picture three times, when we subsequently asked about the size of portion they wanted,” he says.

Tricking your brain into feeling full
It may sound strange that the participants felt full without actually eating anything. But this is really quite natural, explains Tjark Andersen. How we think about food has a large influence on our appetite. 

“Your appetite is more closely linked with your cognitive perception than most of us think. How we think about our food is very important,” he says, and continues:

“Studies have shown that if you make people aware of different colours of Jelly Beans, even if they have eaten all they can in red Jelly Beans, will still want the yellow ones. Even if both colours taste completely the same.”

Within brain research, these findings are explained with so-called grounded cognition theory.  For example, if you imagine putting your teeth in a juicy apple, the same areas of the brain are stimulated as if you actually take a bite of an apple.

“You will receive a physiological response to something you have only thought about. That’s why we can feel fully satisfied without eating anything,” he says.

A large online experiment
Tjark Andersen and his colleagues are not the first to discover that we can get feel full by looking at pictures of food. Other research groups have previously shown this. 

The new research from Aarhus University is that they examined the number of repetitions needed – and whether variation in the images removes the sense of satiety.

“We know from previous studies that images of different types of food don’t have the same effect on satiety. That’s why you can really feel full after the main course but still have room for dessert. Sweet things are a completely different type of food,” he says.

To investigate whether variation in food completely removes the sense of satiety, Tjark Andersen and his colleagues designed a number of online experiments. They ended up getting more than 1,000 people through their digital experiments.

First they showed a picture of just orange M&Ms. Some participants were shown the picture three times, others 30 times. The group that saw most pictures the M&M felt most satiated afterwards, explains Tjark Andersen.

“They had to answer how many M&Ms between 1 and 10 they wanted. The group which had seen 30 images of orange chocolate buttons, chose a smaller amount than the other two groups.”

Afterwards, they repeated the experiment. This time with M&Ms in different colours. The colours did not change the result.

Finally, they replaced the M&Ms with Skittles. Unlike M&Ss, Skittles taste different depending on the colour.

“If colour didn’t play a role, it must be the imagined taste. But we found no major effect here either. This suggests that more parameters than just colour and flavour have to change before we can make a effect on satiety,” he explains.

Could be used as a weight loss strategy
Since 1975, the number of overweight people worldwide has tripled. According to the WHO, obesity is one of the biggest health challenges facing humans. And the reason why we become too fat is that we eat too much food and too much unhealthy food and we do not take enough exercise.

This is where Tjark Andersen’s results come into the play. Perhaps they can be applied as a method to control appetite, he says. 

“Think if you developed an app based on a Google search. Let’s say you wanted pizza. You open the app. Choose pizza – and it shows a lot of photos of pizza while you imagine eating it. In this way, you could get a sense of satiety and maybe just stop wanting pizza.”

Perhaps his results can best be used to ensure that you don’t start a meal. The participants in the study only chose slightly fewer Skittles or M&Ms, corresponding to less than 50 calories.

“You won’t save many calories unless you completely refrain from starting a meal. But perhaps the method can be used for this as well. It’d be interesting to investigate,” he says.

Social media are overflowing with food
Tjark Andersen and a number of other researchers are studying how food advertisements on social media affect us, because we are constantly being confronted with delicious food. 

A few years ago, an American research group tried to find out how many advertisements with food we encounter on average when we are on social media. The researchers monitored a number of young people and mapped out the content they met.

On average, the young people saw 6.1 of food-related posts in 12 hours. The vast majority of the posts were pictures of food – and more than a third were about desserts or other sweet food.

The internet and, in particular, social media can be a contributory factor in our becoming increasingly overweight. But it may also be the solution.

Only the future will tell.

Posted on Obesity, Weight Loss

The naturally occurring peptide may tackle obesity-related conditions’ ‘root cause’.

Naturally occurring peptide may tackle the ‘root cause’ of obesity-related conditions
Naturally occurring peptide may tackle the ‘root cause’ of obesity-related conditions

Research shows that a peptide (small protein) called PEPITEM could provide a revolutionary approach to reducing the risk of type 2 diabetes and other obesity-related diseases such as hepatic steatosis (fatty liver). 

The researchers used an animal model of obesity to investigate whether PEPITEM, delivered by a slow-release pump, could prevent or reverse the effects that a high fat diet has on the pancreas.  Excitingly, the results showed that administration of PEPITEM significantly reduced the enlargement of insulin-producing cells in the pancreas and also significantly reduced immune cell migration into various tissues. 

The research team was led by Dr Helen MCGettrick and Dr Asif Iqbal from the University of Birmingham’s Institute of Inflammation and Ageing and Institute of Cardiovascular Sciences.  Dr McGettrick said: “We have found a new therapeutic approach that could provide new drugs to tackle the root cause of obesity-related conditions by preventing the damage caused by systemic inflammation.

PEPITEM was first identified in 2015 by Birmingham researchers who described its role in the adiponectin-PEPITEM pathway, which is involved in controlling the onset and severity of auto-immune and chronic inflammatory diseases. 

Obesity causes complex and dramatic changes in metabolism in adipose (fat) tissue, damage to the pancreas, reduced insulin sensitivity and eventually the hyperglycaemia that underpins type 2 diabetes.  It also causes a low-level inflammatory response across the boyd, encouraging white blood cells to enter into many tissues including the visceral adipose tissue (fat stored deep inside the body wrapped around the organs, including the liver and gut) and peritoneal cavity (a thin membrane that encompasses the gut). 

The latest research, published in Clinical and Experimental Immunology, shows that the adiponectin-PEPITEM pathway also connects obesity, the low-level inflammatory response that is driven by it, and changes in the pancreas that precede diabetes. 

The results showed that dosing with PEPITEM while the mice were on a high fat diet significantly reduced the enlargement of insulin-producing beta cells in the pancreas and the number of white blood cells in the visceral adipose tissue and peritoneal cavity, compared to controls. 

The researchers also looked at the potential of PEPITEM to reverse the changes brought on by obesity, by feeding the animals a high fat diet prior to treating with PEPITEM.  Excitingly, they saw similar results.  Dr Asif Iqbal commented: “Until now we have understood very little about how the inflammation that accompanies obesity drives pathology.  These results show us that PEPITEM can both prevent and reverse the impact that obesity has on metabolism.  The next stage is to translate these exciting results into therapeutics that can be used in humans.”

Professor Ed Rainger from Birmingham’s Institute of Cardiovascular Sciences led the team that first identified PEPITEM.  He commented: “We are all very excited about these latest results.  PEPITEM is a naturally occurring peptide.  We have already shown it has effects on several organs and now for the first time, we have shown that PEPITEM is effective

Posted on Diet, Weight Loss

A ‘Keto-like’ diet may be linked to a higher risk of heart disease and cardiac events.

Popular weight-loss diet also associated with higher levels of LDL cholesterol
Popular weight-loss diet also associated with higher levels of LDL cholesterol


The ketogenic or “keto” diet, which involves consuming very low amounts of carbohydrates and high amounts of fats, has been gaining popularity. However, a new study presented at the American College of Cardiology’s Annual Scientific Session Together With the World Congress of Cardiology suggests that a “keto-like” diet may be associated with higher blood levels of “bad” cholesterol and a twofold heightened risk of cardiovascular events such as chest pain (angina), blocked arteries requiring stenting, heart attacks and strokes.

“Our study found that regular consumption of a self-reported diet low in carbohydrates and high in fat was associated with increased levels of LDL cholesterol— or “bad” cholesterol—and a higher risk of heart disease,” said Iulia Iatan, MD, PhD, attending physician-scientist at the Healthy Heart Program Prevention Clinic, St. Paul’s Hospital and University of British Columbia’s Centre for Heart Lung Innovation in Vancouver, Canada, and lead author of the study. “To our knowledge, our study is one of the first to examine the association between this type of dietary pattern and cardiovascular outcomes.”

Carbohydrates are the body’s first “go-to” source for fuel to provide energy for daily life. Low-carbohydrate, high-fat (LCHF) diets, like a keto diet, restrict consumption of carbohydrates (e.g., bread, pasta, rice and other grains, baked goods, potato products such as fries and chips, and high-carbohydrate fruits and vegetables). By depriving the body of carbohydrates, it is forced to start breaking down fat for energy instead. The breakdown of fat in the liver produces ketones, chemicals that the body uses as energy in the absence of carbohydrates—hence the name ketogenic, or “ketone producing.” Proponents of a ketogenic diet generally suggest limiting carbohydrates to 10% of total daily calories, protein to 20% to 30% and obtaining 60% to 80% of daily calories from fat.

Some previous studies have shown that an LCHF diet can lead to elevated levels of LDL cholesterol in some people. While elevated LDL cholesterol is a known risk factor for heart disease (caused by atherosclerosis, a buildup of cholesterol in the coronary arteries), the effects of an LCHF diet on risk for heart disease and stroke have not been well studied, Iatan said.  

For this study, Iatan and her colleagues defined an LCHF diet as consisting of no more than 25% of total daily energy or calories from carbohydrates and more than 45% of total daily calories from fat. They dubbed this an LCHF diet and “keto-like” because it is somewhat higher in carbohydrates and lower in fat than a strict ketogenic diet. They defined a “standard diet” as individuals not meeting these criteria and having more balanced eating habits.

The research team analyzed data from the UK Biobank, a large-scale prospective database with health information from over half a million people living in the United Kingdom who were followed for at least 10 years. Upon enrollment in the biobank, 70,684 participants completed a one-time self-reported 24-hour diet questionnaire and, at the same time, had blood drawn to check their levels of cholesterol. The researchers identified 305 participants whose questionnaire responses indicated that their diet during the 24-hour reporting period met the study’s definition of an LCHF. These participants were matched by age and sex with 1,220 individuals who reported eating a standard diet. This resulted in 73% of the participants in each group being women and the group’s average age was 54 years. Those on an LCHF diet had an average body mass index (BMI) of 27.7; those on a standard diet, 26.7. A BMI of 25 to 30 falls within the overweight range.

Compared with participants on a standard diet, those on an LCHF diet had significantly higher levels of both LDL cholesterol and apolipoprotein B (apoB), the protein component that sits on LDL and other atherogenic lipoprotein particles. Previous studies have shown that elevated apoB may be a better predictor than elevated LDL cholesterol for risk of cardiovascular disease, Iatan said. After an average of 11.8 years of follow-up—and after adjustment for other risk factors for heart disease, such as diabetes, high blood pressure, obesity and smoking—people on an LCHF diet had more than two-times higher risk of having several major cardiovascular events, such as blockages in the arteries that needed to be opened with stenting procedures, heart attack, stroke and peripheral arterial disease. In all, 9.8% of participants on an LCHF diet experienced a new cardiac event, compared with 4.3% of those on a standard diet, a doubling of risk for those on an LCHF diet.

“Among the participants on an LCHF diet, we found that those with the highest levels of LDL cholesterol were at the highest risk for a cardiovascular event,” Iatan said. “Our findings suggest that people who are considering going on an LCHF diet should be aware that doing so could lead to an increase in their levels of LDL cholesterol. Before starting this dietary pattern, they should consult a health care provider. While on the diet, it is recommended they have their cholesterol levels monitored and should try to address other risk factors for heart disease or stroke, such as diabetes, high blood pressure, physical inactivity and smoking.”

The study’s findings also suggest that not everyone responds to an LCHF diet in the same way.

“On average, cholesterol levels tend to rise on this diet, but some people’s cholesterol concentrations can stay the same or go down, depending on several underlying factors,” Iatan said. “There are inter-individual differences in how people respond to this dietary pattern that we don’t fully understand yet. One of our next steps will be to try to identify specific characteristics or genetic markers that can predict how someone will respond to this type of diet.”   

A limitation of the study is that participants provided dietary information at only one point in time, which should be considered when interpreting the study findings, Iatan said. Moreover, self-reports of food consumption can be inaccurate, though Iatan said this questionnaire has been extensively validated.    

Because the study was observational, it can only show an association between the diet and an increased risk for major cardiac events, not a causal relationship. However, Iatan said the findings merit further research in prospectively designed studies, especially when approximately 1 in 5 Americans report being on a low-carb, keto-like or full keto diet.

Posted on Diet, Weight Loss

Keto vs vegan: Study of popular diets finds over fourfold difference in carbon footprints

Keto and paleo diets were found to be the least sustainable -- and have the lowest diet quality scores -- of the six popular diets examined
Keto and paleo diets were found to be the least sustainable — and have the lowest diet quality scores — of the six popular diets examined

This may be tough to swallow for those on keto or paleo diets.

A new study from Tulane University which compared popular diets on both nutritional quality and environmental impact, found that the keto and paleo diets, as eaten by American adults, scored among the lowest on overall nutrition quality and were among the highest on carbon emissions.

The keto diet, which prioritizes high fat and low carbs, was estimated to generate almost 3 kg of carbon dioxide for every 1,000 calories consumed. The paleo diet, which eschews grains and beans in favour of meats, nuts and vegetables, received the next lowest diet quality score and also had a high carbon footprint, at 2.6 kg of carbon dioxide per 1,000 calories.

The study, published in The American Journal of Clinical Nutrition, compiled diet quality scores using data from more than 16,000 adult diets collected by the CDC’s National Health and Nutrition Examination Survey. Individual diets were assigned point values based on the federal Healthy Eating Index and average scores were calculated for those eating each type of diet.

The study’s senior author Diego Rose, professor and nutrition program director at Tulane University School of Public Health and Tropical Medicine, said that while researchers have examined the nutritional impact of keto and paleo diets, this is the first study to measure the carbon footprints of each diet, as consumed by U.S. adults, and compare them to other common diets.

“We suspected the negative climate impacts because they’re meat-centric, but no one had really compared all these diets – as they are chosen by individuals, instead of prescribed by experts – to each other using a common framework,” Rose said.

On the other end of the spectrum, a vegan diet was found to be the least impactful on climate, generating 0.7 kg of carbon dioxide per 1,000 calories consumed, less than a quarter of the impact of the keto diet. The vegan diet was followed by vegetarian and pescatarian diets in increasing impact.

The pescatarian diet scored highest on nutritional quality of the diets analyzed, with vegetarian and vegan diets following behind.

The omnivore diet – the most common diet, represented by 86% of survey participants – sat squarely in the middle of the pack of both quality and sustainability. Based on the findings, if a third of those on omnivore diets began eating a vegetarian diet, on average for any given day, it would be equivalent to eliminating 340 million passenger vehicle miles.

Notably, however, when those on omnivorous diets opted for the plant-forward Mediterranean or fatty meat-limiting DASH diet versions, both carbon footprints and nutritional quality scores improved.

“Climate change is arguably one of the most pressing problems of our time, and a lot of people are interested in moving to a plant- based diet,” Rose said. “Based on our results, that would reduce your footprint and be generally healthy. Our research also shows there’s a way to improve your health and footprint without giving up meat entirely.”

A 2021 United Nations-backed study found that 34% of greenhouse gas emissions come from the food system. The major share of those emissions come from food production, with beef being responsible for 8-10 times more emissions than chicken production and over 20 times more emissions than nut and legume production.

While the environmental impacts of specific foods have been studied extensively, Rose said this study was important because “it considers how individuals select popular diets that are composed of a wide variety of foods.”

Going forward, Rose still has questions about how to encourage eating habits that are better for people and the planet.

“I think the next question is how would different policies affect outcomes and how could those move us toward healthier, more environmentally friendly diets?” Rose said.

Posted on Diet, Weight Loss

How better planning and behaviour regulation may lead to eating less fat

New research suggests coaching overweight or obese pregnant women to improve their ability to plan and progress toward goals may be key to helping them lower the amount of fat in their diet.

Maternal diet quality affects prenatal development and long-term child health outcomes. Still, the stress that typically increases during pregnancy – often heightened by concern for fetal health and anxiety over impending parenthood – may derail efforts to focus on healthful eating, previous research has shown.  

In this new study, researchers at The Ohio State University set out to identify the pathway between stress and total fat consumption, with a broader goal to evaluate an intervention designed to improve the diets of pregnant women who are overweight or obese.

Through a series of questionnaires and statistical analysis, the team found that two thinking-related skills – planning, and execution of those plans – were weakened in women whose stress was high, and those skill gaps were associated with higher total fat intake.

These two skills are known as executive functions, a set of multiple thinking processes that enable people to plan, monitor behavior and execute their goals.

“People with a higher level of stress tend to have a higher intake of fat, too. If stress is high, we’re so stressed out that we’re not thinking about anything – and we don’t care what we eat,” said lead author Mei-Wei Chang, associate professor of nursing at Ohio State.

“That’s why we focused on executive functions as a mediator between stress and diet. And with this baseline data, we have reasons to believe that designing an intervention around executive functions could improve dietary outcomes,” she said. “I would anticipate the results could be similar for nonpregnant women, because it’s all about how people behave.”

The study was published recently in the Journal of Pediatrics, Perinatology and Child Health.

The 70 women enrolled in the study had a pre-pregnancy body mass index of between 25 (scores between 25 and 29.9 are categorized as overweight) and 45 (scores of 30 and higher are categorized as obese).

The participants completed questionnaires assessing both overall perceived stress and pregnancy-related stress, as well as executive functions – specifically focusing on metacognition, or the ability to plan, and behavior regulation, the ability to execute those plans. They also completed two 24-hour dietary recalls of their calorie intake and consumption of total fat, added sugar, and fruits and vegetables.

“We were really interested in the mediation role of executive functions. The mediator is what makes everything happen,” Chang said. “We wanted to know: If we focus an intervention on executive functions, would that carry through to behavior change in dietary intake?

“Weight loss interventions often involve a prescribed diet or meal plan, and you are told to follow it. But that doesn’t lead to behavior change in the long term.”

Statistical modeling showed that higher perceived stress was associated with a worsened ability to plan and monitor behavior, and that pathway was linked to higher total fat intake. Similarly, higher levels of pregnancy-related stress were associated with a lower ability to plan, which in turn was associated with worsened ability to monitor behaviors related to carrying out the plan – and these factors were linked to higher fat consumption.

These pathways suggested that an intervention designed to lower stress would function as a starting point to improve the diet, and enhancing skills through coaching – emphasizing the ability to plan, including being flexible with planning, and behavior monitoring, particularly when making food choices – would be key to changing eating patterns.

“You need to improve executive functions, and you also need to lower stress,” Chang said. She and colleagues are now analyzing data on the effectiveness of an intervention for the study participants that emphasized stress management and boosting executive function to promote healthy eating.

Executive functions are regulated by a specific region of the brain, and strengths or weaknesses in these skill areas are thought to be affected by a variety of physiological factors. Previous research has found that executive function deficits are more likely to occur in women who are overweight or obese than in women whose weight is categorized as normal.

“Executive function is not well-studied, and it is not related to intelligence. But people with low executive function are unable to make detailed plans and stick to them, and that’s how they get into trouble,” Chang said. “Metacognition and behavior regulation must go hand in hand – that way you have a much better chance to control your behaviors, and then you will eat better.”