RU Fit? Challenge - Week 3 - Energy Balance

Concept: Energy Balance

Challenge: Accumulate 60 "Cardio Points"

• 1 min of low-intensity activity (5 or less on an effort scale) = 1 point
• 1 min of moderate activity (6-7 on effort scale) = 2 points
• 1 min of high-intensity activity (8-10) = 3 points

Energy Balance - Justin Robinson, MA,RD,CSSD,CSCS,FAFS

As a nutrition instructor, I begin the semester with a discussion about energy – its ultimate source (the sun), how it is harvested (via plants), and how we consume energy (from plants or from animals that consume plants).

I further discuss energy balance in humans, which consists of: intake, storage, and output

• Intake: we eat and drink energy (synonymous with Calories) in the form of carbohydrate, fat, protein, and alcohol
• Storage: we store carbohydrate, fat, and protein in the body
• Output: we burn energy through our metabolism and all forms of activity (structured and unstructured)

Once we comprehend the basics of energy balance, we can better interpret why we gain weight and how to lose it.

The first few weeks of the RU Fit? Challenge have emphasized the first component of energy balance – “intake” (making conscious decisions about what we put into our bodies).  This week, the goal is to focus on the latter component – output (aka caloric expenditure).

Any form of energy expenditure provides endless benefits (both acute and long-term) – a vast body of scientific, as well as equivocal, evidence supports this.  Whereas all movement is beneficial, though, not all movement is created equal; walking may be appropriate for a currently sedentary person, but that person should know that in the near future, walking will not be enough.  The American College of Sports Medicine(ACSM) currently recommends 30 minutes of moderate activity at least 5 days per week (minimum of 150 minutes per week) or 20 minutes of vigorous activity at least 3 days per week (ACSM Position Stand).  Walking does not fit into either the moderate or vigorous category.

My goal is not to be harsh, but truthful – I feel some health professionals under-stress the importance of this moderate-to-vigorous activity by recommending their patients or clients to simply walk.  Doing anything is always better than doing nothing, but America is experiencing a health epidemic and lack of exercise intensity and duration contributes greatly to this crisis.

Let us take a moment to discuss the efficiency (or inefficiency, rather) of walking.  We know that one pound of fat equals 3,500 Calories.  Based on this, and the metabolic equations from the ACSM – for a 150-pound person to burn one pound of fat, he/she must:

• Walk (4 mph) for 8 hours and 45 minutes or 35 miles (which fits the 100 Calories per mile estimate)
• Run (8 mph) for 3 hours and 42 minutes or 29.5 miles

So as you begin or continue your weight management quest, please, please do not expect "Biggest-Loser" type of results. Let us do some more math:

• If contestants lose an average of 10 pounds per week, that equals 1.42 pounds per day
• 1.42 x 3,500 = 5,000 Calories (daily deficit)
• Since they are still eating (assume 2,000 Calorie intake), that means they are burning roughly 7,000 Calories each day!
• Remember 100 Calories per mile?  That means they are exercising the equivalent of 70 miles of walking per day.  This is only possible if you live on the Biggest Loser ranch OR if you quit your job and hire a full-time personal trainer.

From a purely mathematical standpoint – burning energy from exercise is a challenge, to say the least.  Reducing energy intake, however, is far more efficient (at least on paper).  Fear not though, the upcoming challenges and educational blogs will surely discuss methods to decrease energy intake.

Now step away from the computer and go earn those cardio points!