This week: Potato as effective as carb gels for boosting performance • Are you ready for the Strong Women Challenge? • Workout before brekkie to boost health benefits • Three factors that predict obesity by adolescence revealed
Potato as effective as carb gels for boosting performance
Consuming potato puree during prolonged exercise works just as well as a commercial carbohydrate gel in sustaining blood glucose levels and boosting performance in trained athletes, scientists report – though it may also have some unwanted side-effects.
‘Research has shown that ingesting concentrated carbohydrate gels during prolonged exercise promotes carbohydrate availability during exercise and improves exercise performance,’ said University of Illinois kinesiology and community health professor Nicholas Burd, who led the research, which was supported by the Alliance for Potato Research & Education; ‘Our study aim was to expand and diversify race-fueling options for athletes and offset flavour fatigue.’
‘Potatoes are a promising alternative for athletes because they represent a cost-effective, nutrient-dense and whole-food source of carbohydrates’ the researchers reported in the Journal of Applied Physiology; ‘Furthermore, they serve as a savoury race fuel option when compared (with) the high sweetness of (carbohydrate) gels.’
The scientists recruited 12 participants who were healthy and devoted to their sport, averaging 267 kilometres per week on their bicycles. All had been training for years. To qualify for the trials, the cyclists had to reach a specific threshold for aerobic fitness and complete a 120-minute cycling challenge followed by a time trial.
Participants were randomly assigned to one of three conditions during the experiments: they would consume either water alone, a commercially available carbohydrate gel or an equivalent amount of carbohydrates obtained from potatoes.
The researchers standardised what the 12 cyclists ate for 24 hours before repeating the 120-minute cycling challenge and time trial, which was designed to mirror typical race conditions. Throughout the exercise, the team measured participants’ blood glucose, core body temperature, exercise intensity, gastric emptying and gastrointestinal symptoms. The researchers also measured concentrations of lactate, a metabolic marker of intense exercise, in participants’ blood.
‘We found no differences between the performance of cyclists who got their carbohydrates by ingesting potatoes or gels at recommended amounts of about 60 grams per hour during the experiments’ Burd said; ‘Both groups saw a significant boost in performance that those consuming only water did not achieve.’
Plasma glucose concentrations went up by a similar amount in those consuming potatoes and gels. Their heart rates increased by a similar amount over the water-only cyclists, and they were faster on the time trial.
Those consuming potatoes experienced significantly more gastrointestinal bloating, pain and flatulence than the other groups, however. This may be a result of the larger volume of potatoes needed to match the glucose provided by the gels, Burd said.
‘Nevertheless, average GI symptoms were lower than previous studies, indicating that both (carbohydrate) conditions were well-tolerated by the majority of the study’s cyclists’ the researchers wrote; ‘All in all, our study is a proof-of-concept showing that athletes may use whole-food sources of carbohydrates as an alternative to commercial products to diversify race-fueling menus’ Burd said.
Source: University of Illinois
Strong Women Challenge starts next week
ActionAid Australia’s annual Strong Women Challenge is calling on all Australians to sign up to the 21-day strength building challenge between 4 and 25 November to raise vital funds to support women’s fight for equality and justice.
Now in its third year, the Strong Women Challenge is an opportunity to become physically stronger while standing in solidarity with women around the world.
‘The Strong Women Challenge is an incredibly unique fundraising challenge’ explains ActionAid Australia’s Executive Director Michelle Higelin; ‘We ask participants to commit to increasing their own strength to symbolically increase the strength and resilience of women in countries like Vanuatu, Cambodia and Kenya. Participants are supported to realise their own inner power and achieve their goals, while funds raised through the challenge go to support and empower women in low-income countries to become leaders within their own communities.’
Participants are supported along the way with workout videos, rewards for fundraising milestones, and a membership to an active online community where they can share personal challenges and successes.
‘By signing up for the Strong Women Challenge, you’re standing up for women’s rights and supporting women’s struggle for equality and justice on a global scale, all while building your own strength and fitness’ says SWC’s Master Trainer Ali Cavill; ‘The Strong Women Challenge is strong, fearless and powered by people, and we’re encouraging all Australians to get involved!’
ActionAid Australia is a member of a global federation working to achieve social justice, gender equality and poverty eradication in more than 45 countries. ActionAid’s programs support women to understand their rights and develop leadership skills, empowering them to advocate for change in their communities. ActionAid also trains and prepares women to lead in humanitarian emergencies, most recently responding to Cyclone Idai in Africa in March 2019, the Indonesian Tsunami in September 2018, and the Rohingya refugee crisis in 2017.
‘Globally, women make up around 70% of people living in poverty, and face injustices on a daily basis’ concludes Higelin; ‘When emergencies, disasters and conflicts strike, women are among the most affected. Funds raised from the Strong Women Challenge will help ActionAid continue to protect women’s rights in emergencies and empower women around the world.’
You, your colleagues, clients and members can get a team together and register for the Strong Women Challenge strongwomenchallenge.org.au where you can choose a fitness goal to complete by the end of the 21 days.
Workout before brekkie to boost health benefits
According to a new study, published in the Journal of Clinical Endocrinology and Metabolism health scientists at the UK universities of Bath and Birmingham found that by changing the timing of when they eat and exercise, people can better control their blood sugar levels.
The six-week study, which involved thirty men classified as obese or overweight and compared results from two intervention groups (who ate breakfast before / after exercise) and a control group (who made no lifestyle changes), found that people who performed exercise before breakfast burned double the amount of fat than the group who exercised after breakfast.
They found that increased fat use is mainly due to lower insulin levels during exercise when people have fasted overnight, which means that they can use more of the fat from their fat tissue and the fat within their muscles as a fuel. To test proof-of-principle the initial study involved only men, but future studies will look to translate these findings for different groups including women.
While this did not lead to any differences for weight loss over six weeks, it did have ‘profound and positive’ effects on their health because their bodies were better able to respond to insulin, keeping blood sugar levels under control and potentially lowering the risk of diabetes and heart disease.
Building on emerging evidence that the timing of meals in relation to exercise can shift how effective exercise is, the team behind this study wanted to focus on the impact on the fat stores in muscles for individuals who either worked out before or after eating and the effect this had on insulin response to feeding.
Dr Javier Gonzalez of the Department for Health at the University of Bath explained: ‘Our results suggest that changing the timing of when you eat in relation to when you exercise can bring about profound and positive changes to your overall health.
‘We found that the men in the study who exercised before breakfast burned double the amount of fat than the group who exercised after. Importantly, whilst this didn’t have any effect on weight loss, it did dramatically improve their overall health.
‘The group who exercised before breakfast increased their ability to respond to insulin, which is all the more remarkable given that both exercise groups lost a similar amount of weight and both gained a similar amount of fitness. The only difference was the timing of the food intake.’
Over the six-week trial, the scientists found that the muscles from the group who exercised before breakfast were more responsive to insulin compared to the group who exercised after breakfast, in spite of identical training sessions and matched food intake. The muscles from those who exercised before breakfast also showed greater increases in key proteins, specifically those involved in transporting glucose from the bloodstream to the muscles.
For the insulin response to feeding after the 6-week study, remarkably, the group who exercised after breakfast were in fact no better than the control group.
The study was led by Dr Rob Edinburgh as part of his PhD. Co-author, Dr Gareth Wallis of the University of Birmingham added: ‘This work suggests that performing exercise in the overnight-fasted state can increase the health benefits of exercise for individuals, without changing the intensity, duration or perception of their effort. We now need to explore the longer-term effects of this type of exercise and whether women benefit in the same way as men.’
Source: University of Bath
Three factors that predict obesity by adolescence revealed
Three simple factors that predict whether a healthy weight child will be overweight or obese by adolescence have been revealed in a new study led by the Murdoch Children’s Research Institute (MCRI).
The research shows three factors: a child’s and mother’s Body Mass Index (BMI) and the mother’s education level – predict the onset or resolution of weight problems by adolescence, especially from age 6 to 7 years onwards.
Each one-unit higher BMI when the child is aged 6 to 7 years increased the odds at 14 to 15 years of developing weight problems by three-fold and halved the odds of resolution. Similarly, every one-unit increase in the mother’s BMI when the child is aged 6 to 7 years increased the odds at 14 to 15 years of developing weight problems by 5% and decreased the odds of resolution by about 10%.
Mothers having a university degree was associated with lower odds of a child being overweight and obese at ages 2 to 5 years and higher odds of resolving obesity issues by adolescence.
Study author MCRI’s Dr Kate Lycett said the prevalence of being overweight/obese at the age of 14 to 15 years was 13% among children with none of these three risk factors at age 6 to 7 years, compared with 71% among those with all risk factors.
Dr Lycett said identifying these three factors may help clinicians predict which children will develop and resolve excess weight with about 70% accuracy.
‘In the case of BMI, it is an objective measure that is easily measured and reflects diet and exercise choices, but is free from the challenges of assessing physical activity and diet in a standard clinical appointment such as recall bias’ she said.
The findings, published in the latest edition of the International Journal of Obesity, also found children who are overweight or obese at 2 to 5 years have a low chance of resolving their weight problems by adolescence when these three risk factors are present.
Data was sourced from 3,469 participants at birth and 3,276 participants at kinder from the Longitudinal Study of Australian Children. The child’s height and weight were measured every two years.
Dr Lycett said until now most studies have overlooked the important questions around which children are likely to become overweight/obese and how it may be resolved.
‘Because clinicians haven’t been able to tell which children will grow up to become teens with excess weight, it’s been hard to target interventions for those most at risk’ she said.
‘The consequences of this are dire, with childhood obesity predicting premature death and being implicated in cardiovascular disease, diabetes and cancer.’
The study examined how combinations of 25 potential short clinical markers such as time breastfeeding and amount of outdoor activity at various ages predict weight issues, as well as resolution, by ages 10 to 11 and 14 to 15 years.
Intriguingly, short questions about poor diet, low physical activity and other common lifestyle factors were not predictive of weight outcomes.
Lead author Professor Markus Juonala, from the University of Turku in Finland, said a simple risk score, which would be easily available to child health clinicians, could help target treatment or prevention.
‘Combining data on these three easily obtainable risk factors may help clinicians make appropriate decisions targeting care to those most at risk of adolescent obesity’ he said; ‘The benefits of removing a focus on those unlikely to need clinical interventions for obesity has largely been ignored, despite an increasing policy emphasis on avoiding wasteful or unnecessary health care.’
Researchers from Turku University Hospital, Deakin University, the University of Melbourne, The University of Auckland, the University of Tasmania and The Royal Children’s Hospital also contributed to the findings.