You are what you eat

Introduction This simulation is called You are what you eat

Problem definition

Most people nowadays want to hit the gym or eat healthy to get fit and at the same time take a long high quality sleep and work effectively. All the success in life and your energy comes from the food (nutrition values) you consume a day and the regime you have. The new year is knocking the door and you want to make sure that you will plan your food and regime effectively so your life is in balance.

Method

Software for System Dynamics simulations Vensim was used to reach results of the problem simulation. The source of the logic inside the model has been extracted from consultations with nutrition specialist whilst the model has been simplified from other aspects that can influence the accuracy of results. For more accurate results presented model need to be tailored for individual needs and with higher granularity of detail.

Model

Model simulates the level of different aspects in 90 days based on input values which comes from person credentials
DCI - daily calories intake - calculated differently for male and female (not considering other genders) as IF THEN ELSE( Gender=1 , ((66.473 + (13.7516 * Weight) + (5.0033 * Height) - (6.755 * Age)) * Stress * Lifestyle) , (655.096 + (9.5634 * Weight) + (1.8496 * Height) - (4.6756 * Age)) * Stress * Lifestyle)
Weight - is dependent on every day level of energy - if the energy level is positive then you are gaining weight if you use more energy than you consumpted then you are losing weight. The ratio is 1kcal = 1g
Recommended sugar intake - based on your DCI and weight the expected level of sugar is calculated to maintain your current situation
Recommended protein intake - based on your DCI and weight the expected level of protein is calculated to maintain your current situation
Recommended fat intake - based on your DCI and weight the expected level of fat is calculated to maintain your current situation
Kidney failure risk - when the amount of sugar consumpted is higher than recommended then there is a raising risk of kidney failure
Heart disease risk - when the amount of sugar consumpted is higher than recommended then there is a raising risk of heart disease
Acne - the more sugar you consume against recommended values the higher probability that your skin will be in inbalance therefore more vulnerable to acne spreading
Bad smell - increased level of protein in body can cause bad smell from mouth and when you are sweating
Diarrhea - your body have to accomodate higher level of blood flow in order to digest more protein. It can cause problems connected with digestive system.
Energy level - difference between energy intake and energy usage
Energy consumed - according to harvested data 1g of fat gives you 9.3kcal, 1g of protein gives you 4.14kcal and 1g of sugar is 4.14ckal therefore
Amount of fat consumed * 9.3 + Amount of protein consumed * 4.14 + Amount of sugar consumed * 4.14
Energy used - according to your daily activities it is easy to calculate your energy consumption - harvested values for different activities from https://www.kaloricketabulky.cz. Coeficient express how much kcal you use per hour of activity per kg of your weight. Also see above explanation of Randomness variable
(Time spent active a day * 2 + Time spent in gym a day * 6 + Time spent working a day * 1.5 + Time spent sleeping a day * 0.6 + Time spent idle * 1.2) * Weight * Randomness of individual

Inputs - are highlighted as green in the model (you have to fill them)

Amount of sugar consumed - how much sugar you daily consume - can be derived by putting down what you ate a day at https://www.kaloricketabulky.cz
Amount of protein consumed - how much sugar you daily consume - can be derived by putting down what you ate a day at https://www.kaloricketabulky.cz
Amount of fat consumed - how much sugar you daily consume - can be derived by putting down what you ate a day at https://www.kaloricketabulky.cz
Age, Height, Initial weight, Gender (1 for male, 2 for female)
Stress - in percentage rate - 1.0 when you have no stress up to 1.5 when you sweating from the daily stress (so you put 1.8 when you are working as bomb difuser)
Lifestyle - in percentage rate - 1.0 when you are doing nothing up to 1.5 when you consider yourself an active person (you do jogging, fitness, sports)
Time spent idle, sleeping, working, active, gym - when you get home and watching TV shows you are idle, when you are doing dishes/not sitting on the couch you are active
Randomness of individual - here little randomness is added because there can be differences in individual understanding of activities. So the overall energy usage can fluctuate +-10%

Results

In order to use the model for simulation I have used two scenarios

First scenario

The source of the first scenario is my friend who is already on diet. He provided me with his body specific and activity values.
Age: 23
Height: 181
Weight: 91
Time spent:
idle - 6
sleeping - 7
working - 5
active - 5
gym - 1
Average amount of protein consumpted: 170g
Average amount of sugar consumpted: 300g
Average amount of fat consumpted: 100g
Stress - 1 (no stress)
Lifestyle - 1.5 (active)

After those values has been inserted into simulation following results has been spotted
DCI 2739 kcal
Weight 82.9 Kg
Results

Second scenario

The source of the second scenario is myself. I dont really care about what I eat so I put food I ate into https://www.kaloricketabulky.cz and got nutrition values (Hodnoty).
Age: 24
Height: 171
Weight: 62
Time spent:
idle - 5
sleeping - 7
working - 10
active - 1
gym - 1
Average amount of protein consumpted: 107g
Average amount of sugar consumpted: 275g
Average amount of fat consumpted: 51g
Stress - 1.4 (stress from simulation deadline)
Lifestyle - 1.2 (couch potato)

After those values has been inserted into simulation following results has been spotted (after 84 days)
DCI 2711 kcal/day
Weight 62.08 Kg
Results

I repeated the second scenario with higher level of nutrition according to recommended values
Age: 24
Height: 171
Weight: 62
Time spent:
idle - 3
sleeping - 8
working - 8
active - 4
gym - 1
Average amount of protein consumpted: 150g
Average amount of sugar consumpted: 300g
Average amount of fat consumpted: 60g
Stress - 1.1 (reduced stress)
Lifestyle - 1.4 (more active)

After those values has been inserted into simulation following results has been spotted (after 84 days)
DCI 2658 kcal/day
Weight 70.2 Kg
Results

Conclusion

First scenario results clearly shows that with inputed values and given activities the subject should be able to put down on weight in 3 months (84 days) time frame from 91kg to 82kg. In second scenario it is clear that the subject is not using any proper regime so the weight is almost stale and fluctuate a bit together with stress level. The second simulation of second scenario with adjusted values is focused on gaining weight which goes up 8kg only by raising level of protein, sugar and fat consumed while the level of activity is also higher. Human body is extremely advanced machine which needs exact inputs to produce various outputs. Despite the fact that many aspects of our body are still unknown the science of gaining and losing weight just works.