Do Carb and Fat Blockers Work?

A carb or fat blocker is not a magic bullet.
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A carb blocker or fat blocker won't act as a magic bullet for slimming. Either might help a little, but the latter option has side effects. You should exercise caution in trying other weight-loss pills because of potentially serious health hazards associated with them.



Carb and fat blockers may help some with weight loss, but they likely won't produce a major benefit.

Carb Blocker Efficacy

Carb blockers are often made of a bean extract called Phaseolus vulgaris, notes an April 2018 study published in Foods. The action of the extract involves slowing or blocking carbohydrate absorption in the intestinal tract by suppressing enzymes that break it down.

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According to the authors, numerous earlier clinical trials demonstrate the potential of the extract to promote weight loss. With this in mind, the scientists undertook a review of research to determine its efficacy.


The Foods study concluded that Phaseolus vulgaris had a "statistically significant" effect in reducing body weight and body fat. It also appeared safe.

Fat Blocker Pill Efficacy

The fat-blocker pill orlistat is designed to be part of a weight-loss program that includes eating a low-fat, low-calorie diet and getting regular exercise, says the Mayo Clinic. It's sold in two forms: the 120-milligram prescription drug Xenical and the 60-milligram over-the-counter drug Alli. Xenical is approved for use in adults with a BMI of 30, and Alli is approved for use in adults with a BMI of 25.


Orlistat decreases the absorption of fat by inhibiting the intestinal enzyme lipase, which breaks down fat into smaller parts. When taken with a meal, orlistat prevents the absorption of approximately 25 percent of the fat consumed, adds Mayo Clinic.

Does this reduced fat absorption result in pounds melting away? The University of California Davis Health Medical Center says studies show it helps people achieve only mild weight loss.


Fat blockers' side effects involve abnormal bowel habits, reports MedlinePlus. These include loose stools, oily stools and difficulty in controlling bowel movements. Other adverse effects are irregular menstrual periods, anxiety, headaches, stomach pain and rectal discomfort.

People who take orlistat may also experience serious problems such as nausea, vomiting and loss of appetite, as well as weakness, severe stomach pain and yellowing of the skin or eyes, notes MedlinePlus. Hives, itching and rash may also occur. If any of these symptoms appear, call your doctor immediately.



Read more: The Most Effective Diet Pills

Safety of Weight-Loss Pills

Do weight-loss pills work? The options on the market today aren't very effective, says UC Davis Health. They help some people in the short run, but the weight tends to come back. In addition, no single drug helps everyone.


A more important question is whether weight-loss pills are safe. The Food and Drug Administration has serious concerns. It reports that hundreds of "miracle" weight-loss pills and products contain ingredients that either haven't been studied on humans or have been banned due to safety issues.

Weight-loss pills are also tainted with ingredients from approved medications used to treat an array of disorders. These include drugs for seizures, high blood pressure and depression, along with diuretics, which can have serious side effects, reports the FDA.


Hidden, potentially harmful ingredients are also found in "natural" weight-loss supplements, notes the FDA. The law doesn't require such products to obtain FDA approval before they're put on the market. Dangers associated with them include heart palpitations, high blood pressure, stroke, seizures and death.

Avoid These Ingredients

Some ingredients in diet pills pose a greater health risk than others. Ephedra, sometimes called ephedrine or ma huang, is a banned stimulant that causes an irregular heart rate, high blood pressure, mood changes, heart attacks, strokes and seizures, says the Mayo Clinic. Bitter orange is an herbal stimulant that is used in some diet pills as a substitute for ephedra, yet it isn't safe because its actions are similar.


Phenylpropanolamine, or PPA, was once used in decongestants: When combined with other decongestants, it can elevate blood pressure and cause a stroke, states UC Davis Health.


Aside from stimulants and decongestants, beware of dietary teas that work as laxatives, cautions UC Davis Health. They can produce pain and constipation over time.

Shopping Advice for Diet Pills

Because of the extreme dangers of some weight-loss pills, research them carefully before purchasing. The Mayo Clinic recommends looking for information on any that you are considering at the Office of Dietary Supplements and the National Center for Complementary and Integrative Health, a database for dietary supplements. Check with your doctor prior to adding a weight-loss pill to your daily regimen.

The FDA says to be on the alert for warning signs of tainted products. These include products marketed in a foreign language or touted to be alternatives to FDA-approved drugs. Be wary of guarantees or unrealistic promises that you'll "lose 10 pounds in a week." View personal testimonials with skepticism.

Healthy Weight-Loss Formula

Sustained weight loss can be difficult, so it's tempting to look for a quick fix or to try products with inflated claims. The American College of Cardiology offers a simple formula: Burn more energy than you consume from food. A reduction of 3,500 calories will result in a loss of 1 pound. With this in mind, if you reduce your food intake by a mere 100 calories per day, you'll lose 10 pounds within a year.

Gimmicky diets are restrictive, which makes long-term adherence challenging and presents the potential for nutrient deficiencies. Conversely, the Mediterranean diet involves eating a broad variety of nutrient-dense foods that promote health. Foods that comprise the diet include fruit, vegetables, nuts, whole grains, olive oil and fatty fish.

Read more: Why the Mediterranean Diet Is Ranked the Best for 2019

Studies link the Mediterranean diet to several health benefits, including weight loss. An April 2018 study published in Nutrition & Diabetes examined the long-term effects of the eating plan on weight and waist circumference. The authors concluded that following the diet may help prevent weight gain and the accumulation of abdominal fat.




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