Posts tagged food
Articles and news from the latest research reports.
Raw Food Not Enough to Feed Big Brains
Eating a raw food diet is a recipe for disaster if you’re trying to boost your species’ brainpower. That’s because humans would have to spend more than 9 hours a day eating to get enough energy from unprocessed raw food alone to support our large brains, according to a new study that calculates the energetic costs of growing a bigger brain or body in primates. But our ancestors managed to get enough energy to grow brains that have three times as many neurons as those in apes such as gorillas, chimpanzees, and orangutans. How did they do it? They got cooking, according to a study published online today in the Proceedings of the National Academy of Sciences.
"If you eat only raw food, there are not enough hours in the day to get enough calories to build such a large brain," says Suzana Herculano-Houzel, a neuroscientist at the Federal University of Rio de Janeiro in Brazil who is co-author of the report. "We can afford more neurons, thanks to cooking."
Humans have more brain neurons than any other primate—about 86 billion, on average, compared with about 33 billion neurons in gorillas and 28 billion in chimpanzees. While these extra neurons endow us with many benefits, they come at a price—our brains consume 20% of our body’s energy when resting, compared with 9% in other primates. So a long-standing riddle has been where did our ancestors get that extra energy to expand their minds as they evolved from animals with brains and bodies the size of chimpanzees?
The connections between the rising rates of chronic disease and the production and consumption of modern foods can no longer be ignored. Our food supply is not healthy, nor is it sustainable. It has changed so dramatically that we have yet to adapt to the changes. Our food supply has been completely adulterated over the past few decades alone, more drastically than during any other time in history.
Snacking and BMI Linked to Double Effect of Brain Activity and Self-Control
ScienceDaily (July 23, 2012) — Snack consumption and BMI are linked to both brain activity and self-control, new research has found.
Snack consumption and BMI are linked to both brain activity and self-control, new research has found. (Credit: © farbkombinat / Fotolia)
The research, carried out by academics from the Universities of Exeter, Cardiff, Bristol, and Bangor, discovered that an individual’s brain ‘reward centre’ response to pictures of food predicted how much they subsequently ate. This had a greater effect on the amount they ate than their conscious feelings of hunger or how much they wanted the food,
A strong brain response was also associated with increased weight (BMI), but only in individuals reporting low levels of self-control on a questionnaire. For those reporting high levels of self-control a stronger brain response to food was actually related to a lower BMI.
This study, which is now published in the journal NeuroImage, adds to mounting evidence that overeating and increased weight are linked, in part, to a region of the brain associated with motivation and reward, called the nucleus accumbens. Responses in this brain region have been shown to predict weight gain in healthy weight and obese individuals, but only now have academics discovered that this is independent of conscious feelings of hunger, and that self-control also plays a key role.
Following these results, academics at the University of Exeter and Cardiff have begun testing ‘brain training’ techniques designed to reduce the influence of food cues on individuals who report low levels of self-control. Similar tests are being used to assist those with gambling or alcohol addiction.
Dr Natalia Lawrence of Psychology at the University of Exeter, lead researcher in both the original research and the new studies, said: “Our research suggests why some individuals are more likely to overeat and put on weight than others when confronted with frequent images of snacks and treats. Food images, such as those used in advertising, cause direct increases in activity in brain ‘reward areas’ in some individuals but not in others. If those sensitive individuals also struggle with self-control, which may be partly innate, they are more likely to be overweight. We are now developing computer programs that we hope will counteract the effects of this high sensitivity to food cues by training the brain to respond less positively to these cues.”
Twenty-five young, healthy females with BMIs ranging from 17-30 were involved in the study. Female participants were chosen because research shows females typically exhibit stronger responses to food-related cues. The hormonal changes during the menstrual cycle affect this reaction, so all participants were taking the monophasic combined oral contraceptive pill. Participants had not eaten for at least six hours to ensure they were hungry at the time of the scan and were given a bowl containing 150 g (four and a half packets) of potato chips to eat at the end of the study; they were informed that potato chip intake had been measured afterwards.
Researchers used MRI scanning to detect the participants’ brain activity while they were shown images of household objects, and food that varied in desirability and calorific content. After scanning, participants rated the food images for desirability and rated their levels of hunger and food craving. Results showed that participants’ brain responses to food (relative to objects) in the nucleus accumbens predicted how many potato chips they ate after the scan. However, participants’ own ratings of hunger and how much they liked and wanted the foods, including potato chips, were unrelated to their potato chip intake.
This study was funded by the Wales Institute of Cognitive Neuroscience.
What this study shows:
- Brain responses to food images vary considerably between individuals.
- Brain responses to food images but not conscious feelings of hunger or desire to eat predict subsequent potato chip consumption.
- Individuals’ reported levels of self-control influence whether this brain response is associated with a higher or lower BMI.
What this study does NOT show:
- Brain responses to food cues cause overeating.
- The associations reported here are true in everyone — only healthy young women were included.
- Whether our brain response and levels of self-control are learned or innate.
Source: Science Daily
How Does Fat Influence Flavor Perception?
ScienceDaily (July 19, 2012) — A joint study carried out by The University of Nottingham and the multinational food company Unilever has found for the first time that fat in food can reduce activity in several areas of the brain which are responsible for processing taste, aroma and reward.
The research, now available in the Springer journal Chemosensory Perception, provides the food industry with better understanding of how in the future it might be able to make healthier, less fatty food products without negatively affecting their overall taste and enjoyment. Unveiled in 2010, Unilever’s Sustainable Living Plan sets out its ambition to help hundreds of millions of people improve their diet around the world within a decade.
This fascinating three-year study investigated how the brains of a group of participants in their 20s would respond to changes in the fat content of four different fruit emulsions they tasted while under an MRI scanner. All four samples were of the same thickness and sweetness, but one contained flavour with no fat, while the other three contained fat with different flavour release properties.
The research found that the areas of the participants’ brains which are responsible for the perception of flavour — such as the somatosensory cortices and the anterior, mid & posterior insula — were significantly more activated when the non-fatty sample was tested compared to the fatty emulsions despite having the same flavour perception. It is important to note that increased activation in these brain areas does not necessarily result in increased perception of flavour or reward.
Dr Joanne Hort, Associate Professor in Sensory Science at The University of Nottingham said: “This is the first brain study to assess the effect of fat on the processing of flavour perception and it raises questions as to why fat emulsions suppress the cortical response in brain areas linked to the processing of flavour and reward. It also remains to be determined what the implications of this suppressive effect are on feelings of hunger, satiety and reward.”
Unilever food scientist Johanneke Busch, based at the company’s Research & Development laboratories in Vlaardingen, Netherlands added: “There is more to people’s enjoyment of food than the product’s flavour — like its mouthfeel, its texture and whether it satisfies hunger, so this is a very important building block for us to better understand how to innovate and manufacture healthier food products which people want to buy.”
Source: Science Daily