Have you heard that eating too little would put your body into “starvation mode” and cause it to start storing fat? Or if you eat less than 1,200 calories a day, will your metabolism stop?
These ideas are common in the world of diets. But are they true? Believe it or not, the answer is no.
Every person who cuts calories to lose weight sees a drop in resting metabolic rate (RMR), the amount of energy expended daily at rest. RMR should not be confused with Total Daily Energy Expenditure (TDEE). RMR is part of TDEE, about 70% to be exact. Seventy percent of the calories you burn in a day don’t involve moving a muscle. So what about the other 30 percent?
Twenty percent of your TDEE comes from movement, including daily activities and exercise. The remaining 10 percent comes from the energy it takes to digest the food and beverages you consume.
Case study of a real life customer
One of my clients, Jane, is in her 50s and 50s, 5’6 and 160 pounds. She had lost 10 pounds in seven weeks, but she had plateaued for the past two weeks.
After cutting calories to lose weight, your RMR decreased – this is normal, natural, and to be expected. Slow down to conserve grease, fuel and resources. The body doesn’t know if it’s running out of available food, so it slows down to protect what it considers valuable fat stores. Some people see a five percent drop in RMR when they lose body fat, while others will see a 25 percent drop, depending on genetics, previous diet attempts, food quality, and source and deficit level. caloric.
Jane ate 1,100 calories a day while losing weight. Once her weight plateaued, she reduced her calories to 800 per day. After two weeks of staying steady at around 800 calories per day, she asked me for help when her weight hadn’t been budgeted.
She said: “Maybe I need to eat more to kick start my metabolism and lose weight.”
I asked him to check his RMR at a local university, which was measured at 1,083. This means that you need 1083 calories per day without moving or eating.
A quick calculation on the ShapeUp.org website says your RMR should be about 1,291 calories per day. Some quick math (1291-1083=208:208/1291=.16) says his RMR slowed about 16 percent from the projected base. First, that’s within the normal range of RMR deceleration with caloric restriction. And second, his metabolism wasn’t broken.
So why isn’t his weight moving?
MOST of the time, the problem with weight loss is little attention paid to nutrition, plus licks, bites, tastes and sips that go unnoticed (food drags). Jane, however, was eating a REAL 800 calorie plan, plus or minus 10 percent.
SHOULD Jane be losing weight by eating 800 calories a day? Yes.
In addition to being a stellar eater and record keeper, Jane also exercised 280 minutes per week (40 minutes per day). That’s great for the everyday person who wants to be healthier and slimmer.
Because we know your true RMR and how much you exercise, we can do the math to see what you need to maintain your weight and how much weight you should lose if you eat 800 calories a day.
RMR + (exercise value in calories/day) + (at least 10% additional RMR for daily movement) + (10% additional RMR to digest food) = TDEE needs MAINTAIN.
1,083 + (40×6 = 240) + (1,083/10 = 108) + (1,083/10 = 108) = 1,539 calories/day to maintain.
What should I have been losing strictly by the numbers?
1,539-800=739. By eating 800 calories per day, he created what should have been a deficit of 739 calories. That multiplied by seven days in a week equals a deficit of 5,173 calories in a week. This is equivalent, roughly speaking, to 1.5 pounds of body fat loss per week. For every 3,500 calorie deficit (approximate calories in a pound of fat), we lose about a pound of body fat. 5173/3500 = 1.5
If Jane was involved in any other diet or weight loss program, she would have been called a fool for eating below her RMR and/or stalling her metabolism. She would have been prescribed an increase from 750 to 1500 calories to “restore her metabolism” so that she could then try to lose weight in a more “sensible” caloric deficit. And that would have been exactly the wrong thing.
If you increased your calories to 1,000 per day, your RMR would have to increase to 1,283 to stay in the same state. Why? If you were eating an extra 200 calories, your RMR would have to increase 200 calories per day just to break even. If you were to increase your calories to the dietary gold standard of 1,200/day, your RMR would have to rise to 1,483/day. Worried about a metabolism that is too slow? Do you want to eat more to “restore”? For every additional calorie you eat, your RMR has to increase by the same amount, or you’ll gain weight instead of losing it.
If you’re not losing weight by eating 800 calories a day and exercising 280 minutes a week, the problem isn’t the RMR or the numbers on paper, but the actual numbers eaten, actual exercise minutes, and effort OR fact that far too many people consider a plateau of five to seven days on the scale to be weight loss. I don’t consider true stagnation to occur unless 10-14 days have passed with no change. Beyond two weeks? SOMETHING has to change.
Strictly by the numbers, it doesn’t make sense that any overweight person who eats 800 calories a day and exercises 280 minutes should be in maintenance mode.
But Jane was trapped. It could have been any number of things unrelated to a broken metabolism and insufficient nutrition. I found out the answer during a brief phone call.
Jane mentioned that she had had a urinary tract infection and had been taking antibiotics. When she felt healthy again, with proper bowel function (her recipe made her constipated) and energy, she increased her calories to 1100 per day. This coincided with her clearing herself of the effects of the infection and the antibiotics. She at first thought that her weight started to move because she increased her calories. But it was just a coincidence.
The reason her weight plateaued was that she had an infection. Also, she was prescribed an antibiotic that causes water retention AND constipation, which was not a problem in her initial weight loss success.
Once her body was clean, the problems causing water retention and constipation were alleviated and the scale was once again able to show the true results of her efforts.
To add things:
- I’m not a fan of undereating, but it has nothing to do with breaking down metabolism. It has to do with the potential for nutritional deficiencies when calories are too low, the unnecessary loss of precious muscle, and how my clients feel mentally, physically, and emotionally if they eat too little.
- I am a fan of eating the maximum of calories and nutrients that one can eat in order to achieve the desired goals. If someone can eat 2,000 calories a day and lose the body fat they want and achieve their ultimate vision, I’m thrilled.
- If 600, 700, or 800 calories a day were a true “metabolism killer,” we wouldn’t have the University of California and hundreds of other bariatric centers promoting 300-600 calories a day for months after surgery. According to the University of Michigan Adult Bariatric Surgery Program, “average weight loss after gastric bypass surgery is approximately 5 to 15 pounds per week for the first 2 to 3 months, with gradual reduction.” to about 1 to 2 pounds a week after the first 6 months or so.” Although I am against bariatric surgery except as a last resort, one cannot argue against the results. They are due, in large part, to the incredibly small volume of food that successful patients consume. Do your metabolisms slow down? Yes. And they lose a ton of weight anyway, as we expected.
