People losing an average of 17 lbs over six months had a reduction in total calories burned per day of 120 calories per day according to a recent study. This included a decrease in resting metabolism of 138 calories per day. The greater the weight loss, the greater the decrease in total calorie burned and in resting metabolism.

“If we restrict the amount of food an animal can eat…, not only does it get hungry, but it actually expends less energy. Its metabolic rate slows down. Its cells burn less energy (because they have less energy to burn). And when it gets a chance to eat as much as it wants, it gains the weight right back,” Gary Taubes writes in his excellent book Why We Get Fat and What To Do About It.

“The same is true for humans.”

“Eventually, our bodies compensate.”

Therefore, as Taubes points out, the advice we have been given by health experts, that losing weight is simply a matter of diet and exercise, ignores this fact, and can only lead to temporary weight loss.

High-nicotine cigarettes increase metabolism more than low nicotine cigarettes according to one study. Resting metabolism increased 6.8 percent after one cigarette of either the high (1.74 mg nicotine) or low nicotine (0.8 mg). However, after several cigarettes metabolism increased more with the high-nicotine cigarettes than the low ones—an increase in metabolism of of 9.8% versus 5.9 percent.

Chronic stress and a high-fat, high-sugar diet decrease stimulation adrenaline receptors involved in burning fat and reducing appetite notes a recent paper.

Obese people’s metabolism does not increase in response to dietary fat the same way that lean people do according to a study from researchers at Maastricht University in The Netherlands.

Resting metabolism slows by 15 calories for every 2.2 pounds that is lost on a low-calorie diet according to a new paper by Eric Doucet and A. Schwartz from the University of Ottawa in Ottawa, Ontario, Canada.

This was true for both men and women.

So if you lose 22 lbs, resting metabolism falls by 150 calories per day.

Resting metabolism slows by 11 calories per day for every 2.2 pounds that is lost from weight loss surgery according to a new paper by Eric Doucet and A. Schwartz from the University of Ottawa in Ottawa, Ontario, Canada.

This was less than the decrease of 15 calories per day seen with weight loss from a low-calorie diet.

Resting metabolism slows by 25 calories per day for every 2.2 pounds that is lost from weight loss due to liposuction surgery according to a new paper by Eric Doucet and A. Schwartz from the University of Ottawa in Ottawa, Ontario, Canada.

This may be because body fat releases leptin, a hormone which decreases appetite and increases metabolism, therefore, by removing fat cells, liposuction may decrease leptin levels, and thus, decrease resting metabolism.

Studies have shown that giving leptin injections “reverse the effects of weight loss on resting [metabolism],” the paper notes.

This was much greater than the decrease of 15 calories per day seen with weight loss from a low-calorie diet, and the 11 calorie decrease seen with weight loss surgery.

Resting metabolism in obese women was similar to that of lean women (1601 calories per day versus 1505 calories per day), however, obese women sat 2.5 hours more each day (12.7 hours versus 10.1 hours), stood 2 hours less each day (2.7 hours versus 4.7 hours) and spent half as much time in activity than lean women (2.6 hours versus 5.4 hours) according to a new study.

This difference in activity accounted for an additional 300 calories burned in lean women.

The authors of the study concluded that “If the obese women adopted the activity patterns of the lean women, including a modification of posture allocation, an additional 300 [calories] could be expended every day.”

Resting metabolism dropped by 11 percent in women who lost 11 percent of their body according to a new study from the Institute of Medicine in Toulouse, France. This decrease in metabolism was maintained after the women’s weight stabilized.

The women lost an average of 22 pounds, dropping from 195 pounds to 173 pounds.

Resting metabolism dropped by 267 calories per day, from 1690 calories to 1423 calories per day.

“To summarize, the present study confirmed that steady weight loss in humans is accompanied by a decrease in [resting metabolism],” the researchers concluded.

Obese people release less fat from fat cells and burn less fat during exercise than lean people a new paper notes.

Animal protein (pork) causes people to burn 1.9 percent more calories per day than vegetable protein (soy) and 3.8 percent more than carbohydrates according to a study from 2000.

“[O]bese subjects participating in [low calorie diet] programs have a weight loss less than half of that predicted,” according to a new study by Steven Heymsfield and colleagues at Merck Research Laboratories in Rahway, New Jersey. In some studies, the weight loss was less than one-fourth of that which was predicted. The reason? Most is probably due to patients not following the prescribed diet or, to a lesser extent, a decrease in metabolism that scientists currently do not recognize in their current calculations the paper concludes.

Overeating does not increase basal metabolism long-term according to a new study from the the Mayo Clinic.

A pill sold in England known as the “Do-Do” pill, which at the time contained 22 mg ephedrine plus 30 mg caffeine plus 50 mg theophylline, increased the number of calories burned by 8 percent per day which represents 153 calories per day or 15 pounds per year.

Green tea increases metabolism by 4 percent per day according to one study.

Oolong tea, which is partially fermented / partially oxidized green tea—all tea comes from the same leaves—has been shown to increase metabolism 2.9 percent per day or about 66 calories.

A high-protein diet attenuates the decrease in metabolism seen following weight loss according to one study.

Males who take vitamins weigh less, have less body fat and have a higher resting metabolism even after accounting for age, calorie intake and calories expended during physical activities than males that do not take vitamins according to a well-respected group of obesity researchers.

Meridia (sibutramine), and I assume other noradrenaline reuptake inhibitors, may increase metabolism slightly. They may increase metabolism in men more than women according to the research.

Replacing fat in the diet with simple sugars increases metabolism according to a recent study.

“Metabolic adjustments occur with weight loss that may contribute to a high rate of weight regain,” according to a paper by Paul McClean from the Division of Endocrinology, Diabetes, and Metabolism at the University of Colorado and others.

Normal weight adults who ate 35 percent more calories than normal for two weeks gained an average of 5.1 pounds according to a new study.

T3 thyroid hormone plays a major role in determining resting metabolism independent of fat-free mass (muscle) according to a new study from Germany.

How much weight will a person gain if they consume an extra 24 calories per day for a year? Men will gain 3.9 pounds in a year, while women will gain 4.6 pounds according to a new study from Denmark. Yikes!