UT Southwestern Medical Center researchers found in a recent study that severely obese women have different brain activity compared to lean women when it comes to responding to food cues without being hungry.
The brain’s reward centers in severely obese women continue to respond to food cues even after they’ve eaten and are no longer hungry, in contrast to their lean counterparts, according to a recent study by a multidisciplinary team at UT Southwestern Medical Center.
Obese Brain vs Lean Brain
The study compared attitudes and the brain activity of 15 severely obese women (those with a body mass index greater than 35) and 15 lean women (those with a BMI under 25).
MRI images of the study participants were taken before and after a meal.
Both groups showed significantly increased activity in the neo- and limbic cortices and midbrain when they were hungry.
After eating, however, that brain activity dropped among lean participants while continuing in their obese counterparts.
Even after eating and reporting they were full, the severely obese women continued to react to pictures of food in much the same way they had when fasting, as exhibited in brain scans.
An Instinct to Keep Eating (Even When Full!)
“Before or after the meal, they’re just as excited about eating,” said Dr. Nancy Puzziferri, Assistant Professor of Surgery at UT Southwestern and senior author of the study. “It seems they have an instinctive drive to keep eating.”
While the appeal of pictured food dropped 15 percent for the lean women after they ate, the severely obese women showed only a 4 percent decline, based on brain scans using functional magnetic resonance imaging (fMRI) to measure brain activity.
After eating, activity in regions in the prefrontal cortex and posterior cingulate cortex significantly changed in the lean group, but not in the obese group.
The obese study participants maintained activation in the midbrain, one of the body’s most potent reward centers.
Study participants had fasted for nine hours prior to testing. They were asked to rate their level of hunger or fullness, then given a brain scan as they viewed pictures of food.
Again, they were asked to rate their level of hunger.
Over the next hour, the women were fed a meal of lean beef or chicken, potatoes or rice, green beans, canned peaches, and iced tea or water.
After eating, the participants went through another battery of hunger/fullness ratings and fMRI scans while exposed to pictures of food.
The obese women showed sustained “hungry” brain activation, even though they reported the same increase in satiation as their lean counterparts.
NOT a Level Playing Field
“These findings may explain why some people with severe obesity report an underlying drive to eat continually despite not feeling hungry,” said Dr. Puzziferri, who specializes in bariatric and weight loss surgery. “In contrast, lean women when full will either stop eating or just sample a food they crave.”
“It’s just not a level playing field – it’s harder for some people to maintain a healthy weight than others.”
The severely obese women in the study, who weighed between 202 and 316 pounds, were candidates for bariatric surgery to lose weight. The study is following these women after surgery to determine if their brain activation patterns change.
The study was conducted at UT Southwestern and VA North Texas Health Care System. Funding for the research came from UT Southwestern and the National Institutes of Health.
Study co-authors from UT Southwestern include Dr. Thomas Carmody, Associate Professor of Clinical Science and Psychiatry; Dr. Carol Tamminga, Chair of Psychiatry, and holder of the Lou and Ellen McGinley Distinguished Chair in Psychiatric Research, and the Communities Foundation of Texas, Inc. Chair in Brain Science; and Dr. Jeffrey Zigman, Associate Professor of Internal Medicine and Psychiatry, and holder of The Diana and Richard C. Strauss Professorship in Biomedical Research and the Mr. and Mrs. Bruce G. Brookshire Professorship in Medicine.
Non-Prescription Weight Loss Help
So now we know for sure that it’s harder for obese women to lose weight.
Many women intrinsically know that, of course (although the study is certainly vindication).
If you are obese, chances are you’ve seen your doctor for ideas, and that’s the best place to start.
And while the medical community works on more effective weight management tools, there are also some proven things you can try on your own, that don’t require a prescription.
Non-Prescription Alli (orlistat)
Alli (orlistat) is an FDA-approved over-the-counter (OTC) medication to enhance weight loss in overweight people, meaning that no prescription is needed to purchase Alli.
It is recommended in combination with a healthy diet for patients older than 18 years.
Alli, which contains 60mg of orlistat, was approved by the agency in 1999 as a reduced and milder version of Xenical, which is a prescription drug that is composed of 120mg of orlistat.
The diet pills were developed and are commercialized by GlaxoSmith Kline (GSK) and may be used by both patients with a Body Mass Index (BMI) higher than 30, which is already considered obesity, or by overweight patients, with a BMI between 27 and 29.
The existence of comorbidities like diabetes or high blood pressure are not preventive from using Alli, but do check with your doctor first if your obesity is combined with other health issues.
History of Alli
Despite the fact that orlistat has been commercialized in the US since 1999, Alli was only approved by the FDA in 2007.
Since it has half the orlistat of prescription Xenical, it’s a less aggressive treatment and can also be used by overweight patients, instead of just obese ones.
It’s currently the only OTC using orlistat as main ingredient.
How Alli Works
The medication is expected to result in weight loss, as it reduces the absorption of dietary fat in the intestines.
It inhibits the normal function of the enzyme lipase, which is present in the digestive tract and is responsible for breaking down dietary fat to increase absorption and storage.
In other words, Alli reduces your body’s ability to break down the dietary fat in your meals.
Alli is taken with the meals (containing up to 30% fat) up to three times per day.
The fat soluble vitamins A, D, E , K and beta carotene aren’t properly absorbed by people using Alli, so a multivitamin should be taken two hours after Alli pills.
The weight loss is on average 5.5 pounds more than when patients make behavioral changes alone, according to a study conducted in 2014.
However, the weight loss results and maintenance is more successful if accompanied by a healthy diet and regular exercise.
The drugmaker states very clearly that it’s no miracle drug, and only promises to help people toward moderate weight loss.
For example, if someone were to lose 10 pounds from dieting, they’d lose 15 by combining their diet with Alli.
Alli Side Effects
Gastrointestinal side effects from taking Alli are the most common, including abdominal pain or discomfort, oily or gas discharge from the anus, oily stools, more frequent or uncontrollable bowel movements, and other less frequent events, such as headache, back pain and upper respiratory infection.
The gastrointestinal side effects can be avoided by limiting the fat content of your meals to the recommended 30%.
Appetite Suppressing Supplements
Many supplements on the market claim to suppress appetite and boost weight loss.
However, very few non-prescription dietary supplements have sufficient evidence to suggest effectiveness in reducing appetite.
These are the few over the counter dietary supplements with scientifically proven potential to suppress your appetite:
Some research shows that garcinia cambogia suppresses appetite and promotes weight loss.
Garcinia cambogia diet pills are one of the most popular weight loss supplements on the market.
Made with an extract derived from the peel of the Garcinia gummi-gutta fruit, garcinia cambogia pills are used to suppress appetite and promote weight loss.
How it works: Garcinia cambogia extract contains hydroxycitric acid (HCA), which studies show may reduce appetite by increasing serotonin levels in your brain and reducing the metabolism of carbohydrates.
Effectiveness: A review of 12 studies found that participants who supplemented with garcinia cambogia containing 1,000–2,800 mg of HCA per day for 2–12 weeks lost an average of 1.94 pounds (0.88 kg) more than those who consumed placebo pills.
Another study of 28 people demonstrated that garcinia cambogia was more effective at reducing appetite, increasing fullness and decreasing hunger than a placebo.
Side effects: Though generally considered safe, consuming garcinia cambogia may lead to side effects in some people, such as headaches, diarrhea, nausea, and irritability.
Green Coffee Bean Extract
Several research studies have demonstrated that green coffee bean extract may reduce appetite and promote weight loss.
How it works: Green coffee beans contain high levels of chlorogenic acid, which may inhibit fat accumulation.
The extract also contains caffeine, which decreases appetite.
Effectiveness: A recent study of people with metabolic syndrome showed that those taking 400 mg of green coffee bean extract per day experienced a significant decrease in waist circumference and appetite compared to a placebo group.
An analysis of three studies found that overweight participants who took either 180 or 200 mg per day of green coffee extract for up to 12 weeks experienced an average weight loss of 6 pounds (2.47 kg) more than those taking placebos.
Side effects: Though green coffee bean extract is generally well tolerated, it may cause headaches and increased heart rate in some people.
Some evidence supports the use of saffron extract as a way to reduce hunger and lose weight.
Saffron extract is a substance derived from the stigma — or the female part of flowers where pollen is collected — of the saffron flower.
How it works: Saffron extract is believed to contain several substances that may increase feelings of fullness by boosting mood.
Effectiveness: One study of 60 overweight women demonstrated that those taking 176 mg of saffron extract per day experienced a significant reduction in snacking and lost more weight than women on a placebo pill.
Though these results are promising, larger and longer-term studies must be carried out to understand saffron’s role in appetite reduction and weight loss.
Side effects: Saffron extract is generally well tolerated but may cause dizziness, fatigue, dry mouth, anxiety, nausea and headache in some people.
Some research has shown that chromium picolinate may be effective in reducing appetite and encouraging weight loss.
Chromium is a commonly used mineral for blood sugar control, hunger reduction and decreased cravings.
How it works: Chromium picolinate is a highly absorbable form of chromium that helps reduce appetite and cravings by impacting neurotransmitters involved in regulating mood and eating behavior.
Effectiveness: A review of 11 studies of 866 overweight or obese people found that supplementing daily with 137–1,000 mcg of chromium for 8–26 weeks led to reductions in body weight by 1.1 pounds (0.5 kg) and body fat by 0.46%.
Side effects: Potential side effects related to chromium picolinate include loose stools, vertigo, dizziness, headaches and hives.
Guar gum is a type of fiber that may be effective in reducing snacking between meals and decreasing overall calorie intake.
How it works: Guar gum acts as a bulking agent in your gut. It suppresses appetite by slowing digestion and increasing feelings of fullness.
Effectiveness: One study found that consuming 2 grams of guar gum per day resulted in significant reductions in hunger and decreased between-meal snacking by 20%.
Other studies demonstrate similar results, indicating that guar gum may be effective in reducing cravings and overall calorie intake.
Side effects: Guar gum may cause adverse side effects, such as abdominal discomfort, diarrhea, cramping, gas and bloating.
With this new study, we now know that there is a difference in brain chemistry between obese and non-obese women.
While this is illuminating, it’s also disappointing. This means that some women will have a more difficult time controlling their appetite, and managing their weight (something that many women already intrinsically know).
On the positive side, this new knowledge should help the medical community better understand the unique challenges of obesity, and hopefully develop more and better tools for treatment.
In the meantime, obese women with overeating issues should stop blaming themselves for any relative lack of control, and make use of whatever tool they feel will safely help them become healthier.
I’d love to hear your thoughts on the matter.
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