Tag Archives: weight gain

Why we gain weight as we age

As we age, it becomes increasingly difficult to control our weight despite keeping caloric intake and exercise intensity constant. One important factor that may be responsible for this age-related effect may be lipid turnover, which decreases in older people, a new study found.

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The study performed by a team at the Karolinska Institutet in Sweden studied the fat cells of 54 men and women over a period of 13 years. During this time, all participants showed decreases in lipid turnover in the fat tissue — the rate at which lipids (i.e. fat) is removed and stored.

Adipose tissue mass (body fat) is determined by the storage and removal of triglycerides in adipocytes, also known as fat cells. The new study found that the participants who didn’t compensate for their lower lipid turnover rate by eating fewer calories or exercising more gained 20% more weight on average.

There is still very little we know about how triglyceride storage and removal in adipocytes works, but what has become increasingly clear is that this balance is critical to body fat mass. Previously, studies suggested that one way to speed up lipid turnover in fat tissue is to exercise more, and the new research seems to support this notion.

“Obesity and obesity-related diseases have become a global problem,” says Kirsty Spalding, senior researcher in the Department of Cell and Molecular Biology at Karolinska Institutet and another of the study’s main authors. “Understanding lipid dynamics and what regulates the size of the fat mass in humans has never been more relevant.”

A 2011 study found that triglyceride removal rate from fat tissue is decreased and the amount of triglycerides stored each year is increased in individuals suffering from obesity. In other words, it becomes increasingly easy to gain weight once you pass a certain threshold. Weight gain begets more weight gain, in a vicious cycle that becomes increasingly difficult to break.

The Swedish researchers also looked at lipid turnover in 41 obese women who underwent bariatric surgery. The women’s weight gain was analyzed over a period of four to seven years post-surgery. The results suggest that those who had a lower lipid turnover rate before surgery managed to actually increase their lipid turnover and maintain their weight loss.

“The results indicate for the first time that processes in our fat tissue regulate changes in body weight during ageing in a way that is independent of other factors,” says Peter Arner, a professor at the Department of Medicine in Huddinge at Karolinska Institutet and one of the study’s main authors. “This could open up new ways to treat obesity.”

The findings appeared in Nature Medicine.

Eating quickly might favor weight gain, study suggests

Japanese researchers found a link between eating speed and weight gain. They interviewed almost 60,000 type 2 diabetes patients about their eating habits and then analyzed the data.

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The satiety mechanism

When people eat too fast, hormones in the gut that relay the “I’m full” signal to the brain aren’t given enough time to work. This means you’ll eat more food, falsely believing you aren’t full yet. More calories result in weight gain.

As partially digested food enters the small intestine, a series of hormones are released into the bloodstream. Cholecystokinin (CCK), is released by the intestines in response to food consumed during a meal. Leptin, another hormone implicated in satiety, is an adiposity signal that communicates with the brain about long-range needs and satiety, based on the body’s energy stores. Research suggests that leptin amplifies the CCK signals, increasing the feeling of being full. By eating too fast, people may not give this intricate hormonal system the needed time to tell the brain that the stomach is full.

Eating slower lowers obesity development

Study authors Haruhisa Fukuda and Yumi Hurst of Kyushu University Graduate School of Medical Sciences in Fukuoka, Japan, confirm this hypothesis in their paper published in the journal BMJ Open.

Researchers measured the participants’ Body Mass Index (BMI) and waist circumference. Obesity is defined as 25 or more BMI points. Next, the participants answered a set of questions about their eating speed (‘fast’, ‘normal’ and ‘slow’), whether they had dinner within 2 hours of sleeping, but also habits concerning after-dinner snacking, skipping breakfast, alcohol consumption frequency, sleep adequacy and tobacco consumption.

The results showed that 21.5% of the slow-eating group was obese, compared to almost 30% of the normal-speed eaters and 45% of the fast-eating group. Slow eaters had an average BMI of 22, normal eaters had a BMI of approximately 23.5, and fast-eaters had an average BMI of 25. Waist circumference was found to be directly proportional to eating speed as well.

No sleep loss, not skipping breakfast and not eating dinner two hours before bed were all associated with a lower BMI.

This is an observational study because researchers did not measure calory intake and physical activity, which could have affected the results in an unknown manner.

Also, the terms ‘fast’, ‘normal’ and ‘slow’ were used by the participants of this study just as a self-evaluation, without a strict definition of the eating speeds, and without timing the participants while eating.

The verdict: eat slow and enjoy your meals, stop living your life on fast forward and take your time to savor the delish in your dish.

“Interventions aimed at altering eating habits, such as education initiatives and programmes to reduce eating speed, may be useful in preventing obesity and reducing the risk of non-communicable diseases,” the authors conclude.


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Holiday season weight gain myth busted – it’s a lot less than most people think

Here comes Christmas, and everybody on TV is suspiciously merry, wishing us a holiday cheer, while reminding us not to go overboard by eating or drinking too much. It seems like every year, at least one major TV station cautions us that the average person gains between 7 and 10 pounds during the holiday season and as such we should all be careful. Self-report studies show that people believe they’ve gained at least 5 pounds over the holiday season. It’s a huge amount by all accounts, no matter how gluttonous people think of themselves. Travis Saunders, an Assistant Professor in Applied Human Science, thought this was fishy and decided to investigate the matter. He reports in the PLOS ONE blog how he eventually tracked down a reliable study that quantified weight gain over the holiday season. What he found is that weight gain over the holidays in only one pound on average, which puts TV estimates and popular perception on thin ice.

Credit: Trainer Jack

Credit: Trainer Jack


The study, published way back in 2000 in the New England Journal of Medicine, followed weight gain in 195 men and women over the course of the year. Between mid-November (Thanks Giving) to mid-January (past the New Year) the authors report an average weight gain of less than one pound. Less than 10% of the participants gained five pounds, a hefty amount but that doesn’t mean we should put everyone under the same roof.

There’s one worrying finding the study makes: the weight gain doesn’t get lost over the rest of the year. Does this mean that over 20 years, people gain on average 20 pounds just from the holiday season alone? If you ask me, I find that unlikely. Of course, people were followed for only one year. If they had been followed for five years, the study might have found the same net weight gain, but a different period of assimilation for all the excess weight.

Anyway, the takeaway is that the five pounds holiday weight gain is a myth blown out of proportion. Despite this, don’t get cocky and be careful with how much and, most important, what you eat.