How long to regulate metabolism




















Sex also matters, since women with any given body composition and age burn fewer calories than comparable men. You can't easily measure your resting metabolic rate in a precise way there are some commercially available tests, but the best measurements come from research studies that use expensive equipment like a metabolic chamber.

But you can get a rough estimate of your resting metabolic rate by plugging some basic variables into online calculators like this one. It'll tell you how many calories you're expected to burn each day, and if you eat that many and your weight stays the same, it's probably correct. The effect happens gradually , even if you have the same amount of fat and muscle tissue.

So when you're 60, you burn fewer calories at rest than when you're Jensen said this continual decline starts as young as age 18 — and why this happens is also another metabolism question researchers haven't answered. There's a lot of hype around "speeding up your metabolism" and losing weight by exercising more to build muscle, eating different foods, or taking supplements. But it's a metabolism myth. While there are certain foods — like coffee, chili, and other spices — that may speed the basal metabolic rate up just a little, the change is so negligible and short-lived, it would never have an impact on your waistline, said Jensen.

Building more muscles, however, can be marginally more helpful. Here's why: One of the variables that affect your resting metabolic rate is the amount of lean muscle you have. At any given weight, the more muscle on your body, and the less fat, the higher your metabolic rate.

That's because muscle uses a lot more energy than fat while at rest see the graphic in section one. So the logic is if you can build up your muscle, and reduce your body fat, you'll have a higher resting metabolism and more quickly burn the fuel in your body. Jensen also noted that it's difficult for people to sustain the workouts required to keep the muscle mass they gained. Overall, he said, "There's not any part of the resting metabolism that you have a huge amount of control over.

The control tends to be relatively modest, and unfortunately, it also tends to be on the downside. While it's extremely hard to speed the metabolic rate up, researchers have found there are things people do can slow it down — like drastic weight loss programs.

For years, researchers have been documenting a phenomenon called "metabolic adaptation" or "adaptive thermogenesis": As people lose weight, their basal metabolic rate — the energy used for basic functioning when the body is at rest — actually slows down to a greater degree than would be expected from the weight loss.

To be clear: It makes sense that losing weight will slow down the metabolism a bit, since slimming down generally involves muscle loss, and the body is then smaller and doesn't have to work as hard every minute to keep running. But the slowdown after weight loss, researchers have found, often appears to be substantially greater than makes sense for a person's new body size. In the newest scientific study to document this phenomenon, published in the journal Obesity , researchers at NIH followed up with contestants from season eight of the reality TV show The Biggest Loser.

By the end of the show, all of the participants had lost dozens of pounds, so they were the perfect study subjects to find out what happens when you lose a dramatic amount of weight in a short period of time.

The researchers took a number of measurements — bodyweight, fat, metabolism, hormones — at both the end of the week competition in and again, six years later, in Though all the contestants lost dozens of pounds through diet and exercise at the end of the show, six years later, their waistlines had largely rebounded.

Thirteen of the 14 contestants in the study put a significant amount of weight back on, and four contestants are even heavier today compared with before they went on the show. But the participants' metabolisms had vastly slowed down through the study period.

Their bodies were essentially burning about calories fewer about a meal's worth on average each day than would be expected given their weight. And this effect lasted six years later, despite the fact that most participants were slowly regaining the weight they lost. Sandra Aamodt, a neuroscientist and author of the forthcoming book Why Diets Make Us Fat , explained this may be the body's way of vigorously defending a certain weight range, called the set point.

Once you gain weight, and keep that weight on for a period of time, the body can get used to its new, larger size. When that weight drops, a bunch of subtle changes kick in — to the hormone levels, the brain — slowing the resting metabolism, and having the effect of increasing hunger and decreasing satiety from food, all in a seeming conspiracy to get the body back up to that set point weight.

In the Biggest Loser study, for example, the researchers found each participant experienced significant reductions in the hormone leptin in their bloodstreams. Leptin is one of the key hormones that regulate hunger in the body. By the end of the Biggest Loser competition, the contestants had almost entirely drained their leptin levels, leaving them hungry all the time. At the six-year mark, their leptin levels rebounded — but only to about 60 percent of their original levels before going on the show.

But not every kind of weight loss in every person results in such devastating metabolic slowdown. For example: That great effect on leptin seen in the Biggest Loser study doesn't seem to happen with surgically induced weight loss. Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician. Thanks for visiting. Don't miss your FREE gift.

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Is a common pain reliever safe during pregnancy? Can vaping help you quit smoking? Staying Healthy The truth about metabolism March 30, This natural appetite control seems to fade as people get older.

Unless you pay close attention, big meals can quickly add up. What to do: As you get older, it is important to make exercise a regular part of every day. By staying active and sticking with smaller portions of healthy foods, you can ward off weight gain as you age.

Obesity: the problem and its management. Endocrinology: Adult and Pediatric. Philadelphia, PA: Elsevier Saunders; chap The effect of green tea extract on fat oxidation at rest and during exercise: evidence of efficacy and proposed mechanisms.

Adv Nutr. PMID: pubmed. Maratos-Flier E. Williams Textbook of Endocrinology. Philadelphia, PA: Elsevier; chap Could capsaicinoids help to support weight management? A systematic review and meta-analysis of energy intake data. Editorial team. Can you boost your metabolism? Here are the facts on 6 metabolism myths. Myth 1: Exercise boosts your metabolism long after you stop.

Myth 2: Adding muscle will help you lose weight. Myth 3: Eating certain foods can boost your metabolism. Myth 4: Eating small meals during the day increases your metabolism. Myth 5: Getting a full night's sleep is good for your metabolism. Myth 6: You will gain weight as you age because your metabolism slows down.



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