Eating Less May Not Extend Human Life: Caloric Restriction May Benefit Only Obese Mice

ScienceDaily (2009-01-26) -- Caloric restriction only benefits obese mice, according to a new study in the Journal of Nutrition. The results suggest that caloric restriction may not be a universally beneficial anti-aging strategy, as commonly believed.

I've blogged about the topic of calorie requirements a few times here. Despite what some diet "gurus" might say in order to sell you books, pills, and short term "solutions" that are really "illusions". Here's the truth:

A CALORIE RESTRICTED LIFESTYLE IS DETRIMENTAL TO LONG TERM FAT LOSS AND PRESERVATION OF LEAN MUSCLE.

Yes a caloric deficit is necessary to reduce your body weight, but that deficit should be a safe one. 15-20% of your body's energy requirements.

It's hard to pin down a clear definition here. To me, the term "calorie restriction" means that you are restricting your body from obtaining the calories and nutrients necessary for healthy functioning. I think knowing your body's requirements is the first step in avoiding this state.

It isn't all that hard to figure out your caloric requirements. It just takes a scale, a $15 pair of body fat calipers (or a scale that gives you your bodyfat%), and some simple math. In fact, you don't even have to do the math. I've already done that for you in my Total Daily Energy Expenditure calculator - which is always right here near the top right of this blog.

Let me refer you to an oldie but goodie that I posted a while back:

How Many Calories Should I Eat Each Day?

TDEE Calculator Online!

Based on my most recent blog posting, How Many Calories Should I Eat Each Day?, I added a TDEE calculator to the Positive Charge Blog permanently. It's on the right side of the page. Remember, once you know how many calories your body is burning on a given day, you can adjust your calorie intake accordingly to achieve your goal of fat loss, muscle gain, or maintenance!

How Many Calories Should I Eat Each Day?

If you really want to develop a nutrition plan that works for you, the first step you must take is to determine how many calories your body is burning every 24 hours. We call this number TDEE - Total Daily Energy Expenditure. Once you know your daily calorie expenditure, you can determine your daily calorie requirement to acheive your specific goal. A safe rule of thumb is to subtract 15-20% from your TDEE for safe fat loss (negative calorie balance), add 15-20% for safe weight gain (positive calorie balance), or for you lucky ones who are already at their ideal weight just use your TDEE calorie number as your daily calorie intake to maintain your physique.

(Remember, though the following formula is highly accurate, it is based on averages. Caloric expenditure and requirements can vary widely; specifically for athletes, extremely active individuals, and people with medical conditions that effect metabolic rate.)

DETERMINE YOUR DAILY CALORIE NEEDS:

1) Determine your Basal Metabolic Rate (BMR) – this is the number of calories your body will burn over 24 hours in a resting state – before factoring in your daily activity level.

Do you know your body fat percentage? If yes, use formula B for the most accurate BMR result. If no, use formula A. (if you are obese or very muscular, formula B is best for you, so find out your bodyfat %)

A. For Men:
Your BMR = 66 + (13.7 X your bodyweight in kg) + (5 X your height in cm) - (6.8 X your age in years)

For Women:
Your BMR = 655 + (9.6 X your bodyweight in kg) + (1.8 X your height in cm) - (4.7 X your age in years)

B. For Men and Women:
Your lean bodyweight = your total body weight – (your total bodyweight X your bodyfat percentage)

Your BMR = 370 + (21.6 X your lean bodyweight in kg)

Multiply inches by 2.54 to get centimeters
Divide lbs by 2.2 to get kilograms

2) Now multiply your BMR by one of the following numbers from the following chart to determine your Total Daily Energy Expenditure (TDEE):

1.2 .......... You are Sedentary (little or no exercise, desk job)
1.375 .......... You are Lightly active (light exercise or sport)
1.55 .......... You are Moderately active (moderate exercise or sports)
1.725 .......... You are Very active (intense exercise or sports)
1.9 .......... You are Extremely active (intense exercise of more than 2 hours, two-a-day workouts, intense exercise plus a physically demanding job)

3) Adjust your TDEE according to your goal.

LOSE FAT:
You need to create a SAFE negative calorie balance. It is well known that cutting calories too much slows down the metabolic rate, and causes loss of lean mass, so the question is how much should you cut? The American College of Sports Medicine (ACSM) recommends that calorie levels never drop below 1200 calories per day for women or 1800 per day for men. Even these calorie levels are extremely low. Reducing calories by 15-20% below your TDEE is a good place to start.

GAIN MUSCLE:
To gain lean bodyweight, you have to take in more calories than you burn, PLUS be participating in a proper resistance-training program designed to induce creation of new muscle tissue. Add an additional 15 - 20% onto your TDEE to find your recommended intake for muscle gain. Of course, of these extra calories, give your body the right nutrients to build muscle with, namely lean protein and fresh vegetables.

4) Make incremental, safe adjustments to your calorie consumption
Never make huge jumps in your caloric intake. Whatever you’ve been consuming on a regular basis, your body has become used to it. To suddenly jump 1000 calories in either direction can screw up your energy levels, cause rapid fat gain and a host of other problems. If your current intake does not match up with your newly discovered TDEE/Calorie Requirement, you’ll have to gradually adjust to get to that point. Add or subtract 200-300 weekly to get your body safely acclimated to your new calorie intake.