1) [28/04, 7:43 pm] Dr.Dinesh Datta: Check out concept of SDA(Specific Dynamic Action)
[28/04, 7:50 pm] Dr. Avinash Kumar Gupta: Specific dynamic action (SDA), also known as the thermic effect of food (TEF), refers to the energy expenditure associated with the digestion, absorption, and metabolism of food. Essentially, it's the energy your body uses to process the food you eat. Different macronutrients have different SDA rates. For example, protein has a higher SDA compared to fats or carbohydrates. This means that your body burns more calories digesting and metabolizing protein compared to other nutrients.
[28/04, 7:50 pm] Dr. Avinash Kumar Gupta: How clinician can use this info for this case?
[28/04, 8:02 pm] Dr.Dinesh Datta: Basically..
BMR is the energy your body needs to function at rest.SDA(aka thermic effect/dietary induced thermogenesis) is extra energy your body burns to process food.It covers digestion,absorption and storage of nutrients from what you eat.Proteins have high SDA,requiring more energy to process compared to carbs and fats.
Sda is another layer over BMR in understanding total energy expenditure in body.
Total energy expenditure is BMR+SDA+Activity level
Basically we say,bmr is engine size of your metabolism and sda is fuel efficiency.
By understanding TEE,we can tailor/better understand weight gain/loss
[28/04, 8:03 pm] Dr. Avinash Kumar Gupta: Useful
2) To calculate your Basal Metabolic Rate (BMR), we can use the Harris-Benedict equation.
For males:
BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age in years)
First, we convert your height to centimeters:
5 feet 5 inches = 165.1 cm (1 foot = 30.48 cm, 1 inch = 2.54 cm)
Now, plug in the values:
BMR = 88.362 + (13.397 × 81.5) + (4.799 × 165.1) - (5.677 × 30)
BMR ≈ 88.362 + 1093.955 + 791.334 - 170.731
BMR ≈ 1803.92 calories per day
So, your Basal Metabolic Rate (BMR) is approximately 1803.92 calories per day. This is the number of calories your body needs to maintain basic physiological functions at rest.
3) [19/04, 7:06 am] Dr. Avinash Kumar Gupta: Cgpt
The estimation of calories burned during activities like walking involves several scientific methods and studies. The calorie expenditure for an activity like walking is typically determined through experiments that measure energy output in controlled settings. Here’s a brief outline of how scientists might arrive at such data:
1. **Metabolic Measurements**: One common method to determine calories burned is through direct and indirect calorimetry. Direct calorimetry measures the amount of heat the body emits, but it’s complex and not widely used. Indirect calorimetry is more common and measures oxygen consumption and carbon dioxide production. Since the body needs oxygen to burn nutrients for energy, and produces carbon dioxide as a byproduct, measuring these gases can give a reliable estimate of energy expenditure.
2. **Using Metabolic Equivalents (METs)**: The concept of METs (Metabolic Equivalents) is often used. One MET is defined as the energy it takes to sit quietly, equivalent to a calorie expenditure of 1 kcal/kg/hour. Physical activities are assigned MET values based on how much harder your body works relative to sitting quietly. For example, walking at a mild pace (about 3-4 mph) typically has a MET value of around 3.0 to 4.5 METs.
3. **Calculations Based on METs**:
- First, the MET value is multiplied by the person’s body weight in kilograms.
- Then, this number is multiplied by the duration of the activity in hours to find the total caloric expenditure.
For instance, if walking at a mild pace has a MET value of 3.5, an 80 kg person walking for 1 km (which they might complete in about 10-15 minutes, or about 0.2 hours), the calculation would be:
\[
\text{Calories burned} = 3.5 \text{ METs} \times 80 \text{ kg} \times 0.2 \text{ hours} = 56 \text{ kcal}
\]
(Note: This is just an example; actual values might vary based on the specific speed and individual metabolism).
4. **Field Studies and Adjustments**: Scientists also conduct field studies where they monitor real-life activities rather than controlled laboratory settings. They might use portable devices that track physiological responses like heart rate, breathing rates, and even sweat rates to estimate energy expenditure more accurately in day-to-day activities.
5. **Calibration and Validation**: Any method used to calculate or estimate caloric expenditure is usually calibrated against more established methods (like those using laboratory equipment) and validated in different populations to ensure accuracy across age, body weight, and fitness levels.
When it comes to the provided data — an 80 kg person burning 80 calories walking 1 km — this might be a slightly simplified or rounded figure used for easy calculation. In actuality, the calories burned can be influenced by factors like walking speed, terrain, efficiency of movement, and individual metabolic differences. The figure could be derived from an average or estimated value that broadly fits the profile and activity described.
[19/04, 7:28 am] Dr. Avinash Kumar Gupta: "Definition
A MET is defined as the resting metabolic rate, that
is, the amount of oxygen consumed at rest, sitting quiet-
ly in a chair, approximately 3.5 ml 02/kg/min (1.2
kcallmin for a 70-kg person).* As such, work at 2 METS
requires twice the resting metabolism or 7.0 ml O,/kg/min
and three METS requires three times the resting
metabolism (10.5 ml 02/kg/min), and so on"
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