In this casual video, I tell stories about some of my patients with MS and the diets they have attempted, be it a paleo, keto, or vegan diet. Are certain diets linked to better results?
Diet
An avocado a day may improve overall diet quality, researchers report
According to a team led by researchers in Penn State’s Department of Nutritional Sciences, eating one avocado per day may improve overall diet quality. Poor diet quality is a risk factor for many diseases, including heart disease, and many American adults have poor diet quality and do not meet key dietary recommendations provided by the Dietary Guidelines for Americans.
This study was led by Kristina Petersen, associate professor of nutritional sciences, and Penny Kris-Etherton, retired Evan Pugh University Professor of Nutritional Sciences, and recently published in the journal Current Developments in Nutrition. The researchers examined how a food-based intervention — one avocado per day — impacts overall diet quality.
“Avocados are a nutrient-dense food, containing a lot of fiber and other important nutrients. We wanted to see if regular intake of this food would lead to an increase in diet quality,” Petersen said. “Previous observational research suggests avocado consumers have higher diet quality than non-consumers. So, we developed this study to determine if there is a causational link between avocado consumption and overall diet quality.”
Petersen stated that because only 2% of American adults are regular avocado consumers, the researchers wanted to determine if including avocados in an individual’s daily diet could significantly increase their diet quality.
Researchers conducted phone interviews with participants before the study began and at a few points throughout to determine what their dietary intake was like in the previous 24 hours and evaluated their diets using the Healthy Eating Index to determine how well they adhered to the Dietary Guidelines for Americans. Adherence to the guidelines was used as a measure of overall diet quality.
The study consisted of 1,008 participants who were split into two groups. One group continued their usual diet and limited their avocado intake during the 26-week study, while the other group incorporated one avocado per day into their diet.
“We found that the participants who had an avocado per day significantly increased their adherence to dietary guidelines,” Petersen said. “This suggests that strategies, like eating one avocado per day, can help people follow dietary guidelines and improve the quality of their diets.”
Although researchers said they were not surprised to see that eating avocados daily improved diet quality, they had not predicted how participants were able to achieve it.
“We determined that participants were using avocados as a substitute for some foods higher in refined grains and sodium,” Petersen said. “In our study, we classified avocados as a vegetable and did see an increase in vegetable consumption attributed to the avocado intake, but also participants used the avocados to replace some unhealthier options.”
According to Petersen, having poor diet quality substantially increases the risk for conditions like heart disease, type 2 diabetes, kidney disease and many other preventable diseases.
“By improving people’s adherence to dietary guidelines, we can help to reduce their risk of developing these chronic conditions and prolong healthy life expectancy,” Petersen said.
Petersen has also conducted similar studies investigating the impact of food-based interventions, including the relationship between pistachios and diet quality, but said that more research is needed to determine what other food-based strategies can be used to improve people’s adherence to dietary guidelines.
“In studies like this one, we are able to determine food-based ways to improve diet quality, but behavioral strategies are also needed to help people adhere to dietary guidelines and reduce their risk of chronic disease,” Petersen said.
Replacing sugar with sweeteners can improve weight loss control over the long-term in adults
New research being presented at this year’s European Congress on Obesity (ECO) in Venice, Italy (12-15 May), suggests that replacing sugar-sweetened food and drinks with low/no energy-sweetened products can help weight control for at least one year after rapid weight loss in adults, without increasing the risk of type 2 diabetes or cardiovascular disease.
The findings of a year-long randomised controlled trial involving adults with overweight and obesity and children in the overweight range from Northern, Central and Southern Europe also found that consumption of sweeteners and sweetness enhancers (S&SE) was associated with greater diet satisfaction, more positive mood, and less cravings and explicit liking for sweet foods in adults.
The results follow a 2023 systematic review of the evidence by WHO, which suggested that replacing free sugars with non-sugar sweeteners did not appear to help with weight control in the long term and could raise the risk of various health problems, including type 2 diabetes and cardiovascular diseases. The report highlighted uncertainty around the evidence between sweeteners and disease outcomes [1].
“Weight maintenance after weight loss is difficult to achieve, and our findings support the use of S&SEs found in many foods and beverages worldwide as alternatives to sugar-sweetened products to help manage weight control in adults with overweight”, says trial lead author Professor Anne Raben from the University of Copenhagen in Denmark. “The findings also provide important information to address the controversies about potential adverse health effects. Until now, safety data have generally come from animal studies using sweetener doses far above the usual intake in humans.”
S&SEs have very high sweetening power but contribute little or nothing to energy intake. Natural and synthesised sweeteners, such as aspartame, stevia, and saccharin, are commonly added to products by the food and drink industry to cut the sugar content, and are consumed by millions of people around the world every day, for example in soft drinks, desserts, and breakfast foods.
However, the safety of these food additives and their use in appetite and weight control has been hotly debated, and little is known about the long-term effects of S&SE on eating behaviour.
Sweeteners show promise for weight control
To provide more evidence, researchers from the SWEET (Sweeteners and sweetness enhancers: Prolonged effects on health, obesity and safety) project, conducted a one-year randomised controlled trial to investigate whether the prolonged use of S&SEs as part of a healthy low-sugar diet could improve weight loss maintenance after rapid weight loss, as well as benefit risk markers for type-2-diabetes and cardiovascular diseases compared to no S&SE consumption.
Participants also completed questionnaires (at the start of the trial and after 2, 6 and 12 months) to assess the effect of S&SEs on diet satisfaction, control overeating, explicit liking and implicit wanting for food, eating behaviour, physical activity, and quality of life.
The trial recruited 341 adults with overweight or obesity (aged 18-65 years, 71% women, body mass index (BMI) ≥25 kg/m2), and 38 children with overweight (6-12 years, 60% girls, BMI-for-age >85th percentile) from Denmark, Spain, Greece, and The Netherlands through web pages, social media, newspapers and registries.
During the first 2 months of the trial, adults were instructed to follow a low-energy diet (the Cambridge Weight Plan) with the aim of achieving at least 5% weight loss. Children received dietary advice to maintain body weight.
In the following 10 months, participants were randomised to either a healthy diet with less than 10% of energy from added sugar allowing for foods and drinks with S&SEs (S&SEs group), or a healthy diet with less than 10% of energy from added sugar not allowing foods and drinks with S&SEs (sugar group).
At the start of the trial and after 2, 6, and 12 months, participants took part in clinical investigation days to measure change in weight, in BMI-for-age z-score in children (a measure of how many standard deviations a child’s BMI is above or below the average BMI for their age and sex), anthropometry, and risk markers for T2D (e.g., glucose and haemoglobin A1c) and CVD (e.g., cholesterol). Participants also completed food frequency questionnaires and urine samples were collected to measure biomarkers of S&SEs, fructose and sucrose to measure compliance [2].
As planned, intake of sugar-rich foods and beverages declined in both groups over the trial, but significantly more in the S&SE than in the sugar group. At the same time, intake of S&SE products increased in the S&SE group and declined in the sugar group. These results were confirmed by urinary biomarker analyses.
The intention-to-treat analyses (including 277 adults who successfully lost 5% or more body weight after the 2-month weight loss period) found that those consuming S&SEs had slightly better weight loss maintenance after 1 year than the sugar group (average weight loss of -7.2kg vs -5.6 kg making a difference of 1.6 kg).
Additionally, in 203 participants who completed all clinical investigations, risk markers for type 2 diabetes and cardiovascular disease did not differ between the groups.
No differences in BMI-for-age z-score or other outcomes were noted in the 22 children who completed the trial. A larger study would be required in more children to determine any potential effect, researchers say.
Sweeteners reduce cravings for sweet foods and improve well-being in adults
In further analyses of eating behaviour, researchers found that adults in the S&SE group reported greater diet satisfaction when eating out, increased positive mood, and lower craving for sweet food at 6 months than the sugar group. In contrast, adults in the sugar group had greater liking for sweet over savoury foods at 6 months and 12 months. However, there were no differences between the groups in reported physical activity or quality of life.
In children, replacing food and drinks with added sugar with sweetened products had no impact on eating behaviour or physical activity. However, inclusion of S&SEs appeared to benefit children with high levels of uncontrolled eating (eating in response to food palatability [tastiness] and the likelihood of over-consuming).
As co-lead author Ms Clarissa Dakin from the Appetite Control and Energy Balance Research Group at the University of Leeds, UK, explains, “Our findings suggest that the inclusion of low/no energy sweetened products may benefit children who show high levels of uncontrolled eating. For these children, being allowed to consume S&SEs led to lower levels of uncontrolled eating at 12 months in comparison to the children who were not allowed to consume S&SE’s. This benefit was not found for children with lower levels of uncontrolled eating. Together, these findings provide important insights for the ongoing re-evaluation of food additive sweeteners by the European Food Safety Authority and other health agencies worldwide.”
Professor Jason Halford, Head of the School of Psychology at the University of Leeds, UK, one of the SWEET co-authors and President of the European Association for the Study of Obesity (EASO), says, “’The use of low calorie sweeteners in weight management has been questioned, in part because of the link between their use and apparent weight gain in observational studies, however, increasingly it is becoming apparent that is not the case in long term studies.”
With so many types of diets being promoted online and on social media, a leading dietitian says flexibility is more sustainable than a rigid diet plan.
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Joyce Patterson, MPH, RDN, BC-ADM, CPT is a registered dietitian and a diabetes care and education specialist at Michigan Medicine in Ann Arbor, U.S., and she says the science points to a balanced approach.
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“We live in a world full of messages to restrict, eliminate, and fast, and misconceptions related to diet trends are common, such as macronutrient or supplement needs,” she explains. For example, the war wages over fats versus carbs, or eggs come in and out of favor every couple of years, and the media and food manufacturers exploit such information to drive what people think about nutrition and increase sales.
“The sheer number of products and programs claiming to ‘reset your metabolism’ or ‘cleanse’ your system indicates that many people are interested in the science. However, few receive comprehensive and reliable nutrition education and cannot discern between marketing ploys and good science. They make food choices and purchase decisions based on minimal or misleading information.”
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What are some diet trends?
In her new book, Think Like A Dietitian, Patterson reviews various diet trends, unpacking the myths around each and where the barriers to success lie.
“For many, diet culture has shaped their relationship with food. From the parental influences of their childhood to the virality of social media today, these beliefs can be deeply ingrained.”
Patterson highlights that many popular diets are based on minimal scientific evidence, but the ketogenic diet and intermittent fasting are highly studied and debated among nutrition researchers and clinicians.
Research cited in the book has shown the ketogenic diet offers short term benefits in rapid weight loss and metabolic disorders including diabetes, but Patterson says there are not enough long‑term studies to determine the long‑term safety of the regimen.
Similarly, the various forms of intermittent fasting have also shown potential as treatments for obesity and cardiometabolic disorders, but for alternate‑day fasting or prolonged fasts, more studies are needed to assess its long‑term safety.
“When certain diets show promising findings in research, many well‑meaning, non‑nutrition clinicians will be quick to recommend these approaches,” Patterson explains. “From low fat to low carb to fasting, the most popular diets are ironically the most restrictive. It is no wonder they tend to be the most unsustainable.”
In ketogenic diets, the initial water loss in the first week alone can show changes on the scale. However, studies also repeatedly show evidence of weight loss in various other eating patterns—regardless of macronutrient composition—without one proving to be more superior to others. In regard to weight loss maintenance, Patterson explains that “research continues to show little difference when comparing various dietary patterns for long-term weight loss.”
What are the issues with diet trends?
“A common practice is that people will apply certain features of a diet, instead of the actual dietary pattern that was researched. Without proper guidance, people may end up practicing unhealthy behaviors that put their health at risk.”
Patterson points out that diet culture can also push people down a path of overly-restrictive eating.
“Not all people push nutrition down the priority list,” she explains. “In fact, some are so aware of their choices that they control themselves straight into hunger. They know their way around a grocery store and leave no package unturned, scanning and comparing nutrition labels.
“While mindfulness is a key tenet in healthy eating, calories and certain food groups have been vilified by diet culture. Whether people are counting calories, carbs, fat, sodium, or other nutrients, the interpretation is often ‘less is more’. Instead of focusing on healthy food choices and overall balance, some people get caught up in the minutiae of nutrients. They feel food is something to be avoided, as opposed to being the fuel that provides power, strength, and protection.”
Following diet trends can also create an attitude which Patterson calls ‘all-or-nothing’. She explains: “Many people are pretty savvy when it comes to diet trends. They keep up with the latest trends and are willing to try new things. They become familiar with terms like ‘macros’ or ‘alkalinity’ or ‘ketones’. When they put their minds to it, they are able to lose weight rather quickly. They know how to slim down for a wedding or a cruise or a beach vacation. When they’re ready, they dive right in and see results.”
However, Patterson explains that when something unexpected happens, such as a social event, a family issue, a health concern, or a stressful event, often these ‘all or nothing’ dieters hit an inevitable plateau, become frustrated, and give up.
“Life happens. And it will happen again and again. These are perhaps the most impactful challenges that people encounter because they are recurring and inevitable. They may be accompanied by an emotional burden such as stress or worry. Or the episode may be followed by feelings of guilt or failure, especially for those whose self‑efficacy was low in the first place. If it happens repeatedly, the cost of the effort may seem to outweigh the benefit, leading to a complete cessation of action. All too often, this cycle of regression repeats itself,” she explains.
What should we do instead?
“In my experience, I find that many diet trends are effective not because they are novel, but because they are similar,” Patterson says.
Research and Patterson’s experience both suggest that most diets work because regardless of whether it monitors calories, carbs, fat, protein or points, it usually follows that some of these basics are applied: added sugar and ultra‑processed foods are limited; plant foods increase; portions are controlled.
“With every new study, there is a new headline, causing whiplash among patients and health professionals alike,” she explains. “Therefore, erring on the side of balance and variety can be a safe way to maneuver some of these controversial and ever‑changing topics.”
Patterson suggests that following an ‘80/20’ rule is more sustainable, acknowledging that dietary perfection is an impractical approach.
“Specifically, this rule of thumb suggests that people follow dietary recommendations 80% of the time, and not to worry about the other 20%, factoring in convenience, enjoyment, and social interactions.
“One of the most important experiences that a dietitian can share is that perfection is not only unattainable but also unnecessary. Even centenarians often admit to some lifelong indulgences.
“A healthy diet does not have to be all-or-nothing. The occasional treat is not harmful. However poor choices in excess can increase risk for nutrition-related disease,” she explains.
Swapping meat for Quorn lowers bad cholesterol by 10 per cent
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Regularly substituting meat for mycoprotein such as Quorn could help to lower bad cholesterol by 10-percent, which is comparable to switching to a Mediterranean or vegan diet.
New research by the University of Exeter, published in Clinical Nutrition, also found substituting meat for Quorn reduces blood glucose and c-peptide concentrations associated with diabetes, cardiovascular disease and all-cause mortality.
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With one in six UK adults suffering from raised cholesterol, the findings indicate that mycoprotein – the high protein, high-fibre food source that’s the main ingredient in Quorn – could play a key role in cholesterol management and improving heart health.
Dr George Pavis, of University of Exeter, led the study and said: “We’re really excited about these results and what they mean for public health. Previous laboratory studies, where all food eaten is controlled and alcohol and caffeine consumption regulated, have clearly shown that daily consumption of mycoprotein reduces bad cholesterol. But this is the first study of its kind to explore the impact of such a dietary intervention in a real-world, home-based setting where participants were not restricted in terms of what else they consumed or did.
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“The findings demonstrate that introducing Quorn foods into a diet on a regular basis helps to significantly lower bad cholesterol, blood glucose and c-peptide concentrations, which is important for boosting heart health and reducing the risk of cardiovascular disease.
“It was particularly interesting to see the scale of the impact that Quorn consumption had in terms of reducing harmful cholesterol, with its performance over four weeks comparable to what we might expect to see from well-established approaches, such as following a Mediterranean diet.”
The remotely delivered study involved 72 overweight adults with high cholesterol levels. Researchers found that participants who ate 180g of Quorn products on a daily basis – equivalent to two servings of Quorn mince – saw a 10-percent reduction in ‘bad’ LDL cholesterol over the four-week study period. This equates to a 0.3 millimole per litre (mmol/l) decrease in bad cholesterol levels in less than one month.
Research has shown how more wholesale healthy dietary changes, such as switching to a Mediterranean or vegan diet, will typically deliver a 0.2 – O.3 mmol/l reduction in bad cholesterol levels after 12 weeks. Researchers at the University of Exeter also noted that typical doses of atorvastatin, the most popular statin prescribed by the NHS to treat high cholesterol, commonly yield a 0.3 – 1.3 mmol/l reduction after 12 months.
According to medical research, a decrease of 0.39 mmol/l in bad cholesterol levels is associated with a 25% lower lifetime risk of heart and circulatory disease. With pharmaceutical trials suggesting that reductions increase in a linear way over time, the researchers suggested further studies should be undertaken to see if the results improve even further when Quorn is eaten over a longer period.
The study – which saw half of the participants (39) given meat and fish products to eat on a daily basis as part of their regular diet, while the other half (33) were provided with Quorn products – also revealed further heart health benefits.
High blood sugar levels and c-peptide concentrations are commonly associated with diabetes and an increased risk of cardiovascular disease and all-cause mortality. The researchers found that study participants who ate Quorn products experienced, on average, a 13-percent drop in blood glucose levels and a 27-percent fall in c-peptide concentrations, compared with the control group. With current data showing that 2.4 million people are at an increased risk of type 2 diabetes in the UK based on high blood sugar levels, these findings demonstrate how mycoprotein could also play a key role in tackling a disease that currently costs an estimated £14 billion a year to treat.
The findings come after the latest annual Health Survey for England estimated that well over half (59-percent) of adults suffer from raised cholesterol and one in ten from diabetes, with both conditions known to cause cardiovascular disease – meaning millions of people could be at risk of a potentially fatal heart attack or stroke.
Sam Blunt, Quorn’s director of sustainability and corporate affairs, said: “The potential cholesterol-lowering effects of Quorn’s mycoprotein were first identified nearly four decades ago and, since then, numerous studies have helped us to understand more about the extent of its cholesterol management capabilities, with its high-fibre content thought to play a key role in this.
“While the benefits of adopting a Mediterranean diet are clear, it’s not always easy to do and this study highlights how, by simply introducing Quorn products into their diet on a regular basis, people may be able to quickly reduce their cholesterol levels and improve their heart health with minimal effort.”