Fat Breakdown is affected by nutrition

Scientists have shown that when either lean or obese individuals exercise after eating a high fat meal, their fats are broken down and oxidized in skeletal muscle, making them healthier. These results show for the first time how a high fat diet and exercise stimulate the breakdown of fats and may help design ways to reduce excessive fat in the body.

Fat is broken down inside fat cells to generate energy by a process called lipolysis. The resulting fatty acids are released into the bloodstream and carried to tissues that require energy. In obese individuals, too much fat accumulates, compromising lipolysis, but the details of how this happens are not well understood. Also, obese individuals can show altered responsiveness to the stress hormones epinephrine and norepinephrine in their subcutaneous fat.

Max Lafontan and colleagues investigated how fat is broken down in both lean and obese subjects who exercised after either fasting or eating a high-fat diet. They noticed that after eating a high-fat diet, fats were broken down in both lean and obese individuals. Under fasting conditions, the breakdown of fats was more pronounced in the lean subjects, but the high fat meal enhanced lipolysis in the obese subjects.

The scientists also studied the effects of long-chain fatty acids (LCFAs) – which are found in high fat diet – on cultured fat cells. They noticed that LCFAs increase lipolysis when it is induced by epinephrine, one of the hormones known to stimulate lipolysis.

By showing for the first time how a high fat diet and LCFAs affect hormone-induced lipolysis in fat cells, this study paves the way for further research on the role of various fatty acids on the metabolism of muscle and blood vessel cells, the researchers conclude.

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Article adapted by MD Only from original press release.
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Article: “Acute exposure to long-chain fatty acids impairs alpha2-adrenergic receptor-mediated antilipolysis in human adipose tissue,” by Jan Polak, Cedric Moro, David Bessiere, Jindra Hejnova, Marie A. Marques, Magda Bajzova, Max Lafontan, Francois Crampes, Michel Berlan, and Vladimir Stich

MEDIA CONTACT: Max Lafontan, Institut National de la Sante et de la Recherche Medicale (French National Institute of Health and Medical Research), Toulouse, France; e-mail: Max.Lafontan@toulouse.inserm.fr

Brisk Walk Helps You Stop Snacking

Researchers at the University of Exeter have found that a walk of just fifteen minutes can reduce chocolate cravings. The benefits of exercise in helping people manage dependencies on nicotine and other drugs have previously been recognised. Now, for the first time, newly-published research shows that the same may be true for food cravings.

Following three days of abstinence, 25 regular chocolate eaters were asked to either complete a 15-minute brisk walk or rest, in a random order. They then engaged in tasks that would normally induce chocolate cravings, including a mental challenge and opening a chocolate bar.

After exercise participants reported lower cravings than after rest. Cravings were not only reduced during the walk, but for at least ten minutes afterwards. The exercise also limited increases in cravings in response to the two tasks.

Professor Adrian Taylor comments: “Our ongoing work consistently shows that brief bouts of physical activity reduce cigarette cravings, but this is the first study to link exercise to reduced chocolate cravings. Neuroscientists have suggested common processes in the reward centres of the brain between drug and food addictions, and it may be that exercise effects brain chemicals that help to regulate mood and cravings. This could be good news for people who struggle to manage their cravings for sugary snacks and want to lose weight.”

Previous research has suggested that 97% of women and 68% of men experience food cravings. Craved foods tend to be calorie-dense, fatty or sugary foods, with chocolate being the most commonly reported. Chocolate has a number of biologically active constituents that temporarily enhance our mood with a result that eating it can become a habit, particularly when we are under stress and when it is readily available, and perhaps when we are least active.

Professor Taylor concludes: “While enjoying the occasional chocolate bar is fine, in time, regular eating may lead to stronger cravings during stress and when it is readily available. Recognising what causes us to eat high energy snacks, even if we have plans to not do so, can be helpful.”

“Short bouts of physical activity can help to regulate how energised and pleasant we feel, and with a sedentary lifestyle we may naturally turn to mood regulating behaviours such as eating chocolate. Accumulating 30 minutes of daily physical activity, with two 15 minute brisk walks, for example, not only provides general physical and mental health benefits but also may help to regulate our energy intake. This research furthers our understanding of the complex physical, psychological and emotional relationship we have with food.”

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Article adapted by MD Only from original press release.
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Contact: Sarah Hoyle
University of Exeter