Introduction

I was inspired to do a fat amount and height comparison between Africans and people from any other continent by two things. One is having heard it enough times that Africans in general have less amount of body fat compared to other parts of the world. I remember asking my trainer why I got so tired while swimming and he told me that generally Africans tend to have less fat and more muscle while it was vice versa for the Europeans for example, and that is why they got so tired. How true that explanation is, I did not know. Even then, I wondered how big this differences were because looking at my colleges in Italy for example, the differences were not as profound as many seemed to note. But before I continue I find it worthwhile to answer the question:

What is fat?

¹Fats are compounds that consist of fatty acids (chains of carbon and hydrogen atoms, with a carboxylic acid group at one end), bonded to a backbone structure, often glycerol. They are stored as fat molecules in fat cells. The majority of fat is stored under the skin or as subcutaneous fat. Fat is also stored in other areas that are dependent on age and the sex of the person. For example, in women there is a high percentage of fat around the breasts, the waist, the hips and the buttocks. In most males, the fat is around the chest, the abdomen and the buttocks. There is also fat storage around important organs like the liver, the heart, the kidneys and even inside muscles for protection. Fats are mainly for provision of energy and to act as insulators.²

The other inspiration through the theory of bipedalism

The other inspiration came from a theory explaining how bipedalism in man came about. This is under evolution theory.

Evolution according to biological science book two is the overall gradual development which is both ordered and sequential. It is also the development of differentiated organisms from pre existing, less differentiated organisms over the course of time.⁴ Bipedalism on the other hand, is the condition of being two footed or using two feet to walk or stand.⁵ It is according to the evolution theory a gradual development from quadrupedalism (condition of being four footed).⁶

Although man has been known to be standing fully upright for only the last 4million years, evidence has been found to show that, actually Ramapithecus, who lived 15 million years ago, had the ability to stand. However, he was only partially erect.⁶The first known fully upright ancestor is Australopithecus afarensis “Lucy” who was discovered by Donald Johanson in 1974. She was about 4million years old. Below are pictures of some cast skulls showing some of modern man’s walking ancestors.

Australopithecus boisei.

Lived around 2.5 million years ago.

Homo habilis

Lived around 2.0 million years ago.

⁷*Recent fossil findings of Homo habilis and Homo erectus in Kenya, suggest a possibility that the two coexisted together. The latter is the smallest skull found of its kind, found anywhere in the world dating back to 1.55 million years ago. The former is an upper jaw bone dating back to 1.44 million years.

Homo erectus (famously known as, Turkana boy)

Lived around 1.5 million years ago.

Homo helmi (African equivalent of Neanderthal man)

Lived around, 0.08 million years ago.

Homo sapiens sapien

Lived around 0.03 million years ago.

*Pictures have been taken Courtesy of the Kenya National Museums, Nairobi.

This idea aroused my curiosity more in wanting to know how exactly how different in terms of fat amount and height Africans, especially those living around the hot places

The theory, which centers on the changing physiological demands that faced our ancestors hence causing bipedalism, has been explained in depth by Pete Wheeler an English Physiologist, and Peter Willow. The former, as narrated by Ian Tattersall in his book The Fossil Trail, ⁸ explains how problems of body temperature regulation, together with a shortage of water challenged our ancestors leading to bipedalism. This was caused by temperature changes that caused the forests to fragment and give over to the hot savannah. The most prominent problem then became cooling the brain and that is where an upright posture came in handy to counter this problem. This is because it minimized the surface area of the body exposed to the sun. Bipedalism also lifted the body of the ground allowing it to be cooled by the wind thus loosing heat by convection and evaporation especially if the skin is not insulated by a hairy coat.( Thus bipedalism provided a good opportunity to loose the hairy coat). It also demanded less energy than a quadrupedal position and hence less internal heat is generated

This theory is made complete and plausible opinion makes it complete and plausible when he talks about the arboreal ancestors of the first human quadrupeds not being committed quadrupeds but rather semi arboreal and having the ability to hold themselves upright. When the forests fragmented, and got replaced with the sun scorching savannah, they began to exploit the new environment and the physiological advantages of the upright posture may have been enough to tip the balance in favour of the bipedal locomotion. This is thus to mean that man’s ancestors did learn to walk upright while still in the forest and not when they moved into the savannah. This is an opinion held by famous paleontologists too like Donald Johanson, Lovejoy and Tim White.⁹ Peter Willow in the documentary “Some liked it hot”, ¹⁰ adds his research findings on the famous Homo erectus fossil remains of the Turkana boy who was already five and a half feet tall when he died.(which is actually very tall for a nine year old boy). He claims that, not only standing upright was vital but also a big body because, although a big body can be useful in retaining heat in cold temperatures, it can also be useful in hot temperatures because it gains heat more slowly, therefore, dehydrates slowly and can live longer without water and hence, longer distances can be traveled. He gives the example of the Turkana people in Kenya who are very tall and lean, an adaptation to the hot temperatures in the savannah.

This again made me think about the differences there would be between the people of Kenya, my country, which is in Africa and the people of Italy where I study, which is in Europe. This is by considering that the two have fairly different temperatures. Kenya has a large part of it, occupied by the hot savannah and a lot of fossil evidence has been found here suggesting that evolution took place. This has given Kenya the title, “Cradle of mankind”. However, I was not going to do my investigation on the main inhabitant’s people of the savannah region if I was to do a comparison with the Italian people. There culture in terms of food, (which is mainly meat, blood and milk because they keep cattle), and their lifestyle, (they are nomads hence they walk a lot all over the plain land) is completely different from the Italians, who live a more relaxed life, with cars to drive them from place to place and so on. So I chose Nairobi, the capital, whose number one advantage is that it is occupied by people from all regions in Kenya. Thus there would be an attempt to represent a major part of Kenya to make the results credible, as different regions have different temperatures too. Its lifestyle is also changing very fast to conform to the western world. Therefore, even though there are differences, they are minimal compared to those that would have been there had I used the savannah inhabitants. It was also more convenient for me to get data in Nairobi because this is where I live and thus time, energy and finances are saved. For the Italian part of the experiment I chose the college where I study, which is in Italy and thus there are Italians from practically every region and thus getting data is easy.

Kenya is situated to the East of Africa and has the equator dividing it along it’s with into almost equal halves.

The three main regions have annual average temperatures of: Mombasa (coastal): Max 30ºC, Min 22ºC Nairobi: Max 25ºC, Min 13ºC North Plain lands: Max 34ºC, Min 23ºC. ¹¹

Italy on the other hand is to the south of Europe. It has different regions each varying in temperature according to its elevation. Places to the south are warmer while those to the north are very cold. It is mainly placed under annual isotherms of 11°C and 19°C. In the Po Plain, the average annual temperature is about 13°C and in the coastal lowlands, about 14°C. ¹²

EXPERIMENT:

Determining the percentage of body fat, relative to body weight and height of the people of Kenya, in comparison with the people of Italy.

Aim:

To determine the amount of body fat relative to body weight of the two groups of people. Thereafter, be able to make a comparison between the two. This will enable one to correctly tell if their amount of fat is similar or different, and the possible reasons for leading to that conclusion, for example temperature, lifestyle and so on.

Requirements:

A trimmeter, a conversion table, a scale, measuring tape, pen, paper, calculator, volunteers (who have their measurements taken). Below is the method on how to use the trimmeter as instructed by the flyer that comes with it.

Method¹⁴:

1. Take a trimmeter in the right hand and ensure the display is reset to Zero.

2. Pinch the skin fold between the thumb and the forefinger. (1cm above the point to be measured)

3. Place the right arm of the trimmeter against the skin fold and bring the left arm into contact with the skin fold to get the correct measurements.

4. Slide the button to retain the measurement.

5. Read the measurements in mm on the display and record on the table shown on the next page.

6. Repeat this for all the recognized measuring points that is, the biceps fold, the triceps fold, the shoulder blade fold and the pelvis fold and also record on the table. The following are diagrams showing the recognized measuring points in the order written above.

7. Determine the age and sex of the person and record on the table.

8. Total up the four skin fold measurements and using the table provided by the trimmeter manufacturers, determine the percentage fat corresponding to the total of the measurements. (Remember to check on the correct table, for male or female and the correct age group).

9. Take the body weight measurement using a scale and record on the table.

10. Calculate the amount of fat in the body using the formula:

Percentage fat * body weight.

11. Take the height of the individual and also record.

Table 1: Table showing the skin fold measurements, age, body weight, amount of fat relative to body weight and height of Kenyan females

Biceps fold in mm	Triceps fold in mm	Shoulder blade fold, in mm	Pelvis fold, in mm	Total for all folds in mm	Age, in years	% fat from conversion table	Body weight, in kilograms	Amount of fat, relative to weight in kilograms	Body Height, in cm
11	16	20	15	62	19	29.6	51	15.1	165
15	17	13	20	65	20	30.3	58	17.6	168
13	20	10	15	58	17	28.7	63	18.1	161
10	24	13	9	56	19	28.1	52	14.6	161
13	19	14	20	66	20	30.4	55	16.7	168
12	18	10	10	50	18	26.5	50	13.3	174
11	15	12	10	48	19	25.9	54	14.0	168
15	20	15	15	65	17	30.3	62	18.8	170
18	24	20	22	82	18	33.5	55	18.4	165

• Average Percentage fat: 29.6 + 30.3 + 28.7 +28.1+30.4 + 26.5 + 25.9+30.3 + 33.5

9

=29.3%

• Average height: 165 + 168 +161 +161 +168 +174 +168 +170 +165

9

= 167cm

Table 2: Table showing the skin fold measurements, age, body weight, amount of fat relative to body weight and height of Kenyan males

Biceps fold, in mm	Triceps fold, in mm	Shoulder blade fold, in mm	Pelvis fold, in mm	Total for all folds, in mm	Age, in years	% fat from conversion table	Body weight, in kilograms	Amount of fat relative to weight in kilograms	Body Height, in cm
5	9	8	7	29	21	12.5	86	16.3	198
9	10	6	10	35	17	14.7	68	14.6	180
6	8	9	10	33	20	14.1	81	16.8	195
5	11	7	8	31	20	13.3	76	15.1	189
6	15	15	14	50	19	19.0	65	17.2	170
15	15	15	18	63	18	21.8	79	23.5	168
10	10	12	10	42	17	17.0	47	11.3	160
7	12	12	11	42	18	17.0	63	15.1	168
7	9	15	15	46	20	18.0	75	19.0	176

• Average percentage fat: 12.5 + 14.7 + 14.1+ 13.3 +19.0+ 21.8 + 17.0 +17.0 + 18.0

9

= 16.3%

• Average height: 198 + 180 + 195 + 189 + 170 + 168 + 160 + 168 + 176

9

= 178.2cm

Table 3: Table showing the skin fold measurements, age, body weight, amount of fat relative to body weight and height of Italian females

Biceps fold, in mm	Triceps fold, in mm	Shoulder blade fold, in mm	Pelvis fold, in mm	Total for all folds, in mm	Age, in years	% fat from conversion table	Body weight, in kilograms	Amount of fat relative to weight in kilograms	Body Height, in cm
20	19	20	17	76	17	32.4	60	19.4	170
10	13	10	9	42	17	24.1	49	11.8	157
19	25	20	20	84	18	33.9	81	27.5	169
17	20	14	15	66	18	30.4	54	16.4	168
21	30	13	14	78	18	32.8	47	15.4	161
15	15	15	15	60	19	29.1	54	15.7	164
26	20	19	30	96*	17	35.6	64	22.8	167
25	21	21	20	87*	19	34.0	56	19.0	160
18	25	17	19	79	20	33.0	62	20.5	165

• Average percentage fat: 32.4 + 24.1 + 33.9 + 30.4 +32.8 + 29.1 + 35.6 +34.0 + 33.0 9

= 31.7%

• Average height: 170 + 157 + 169 + 168 + 161 +164 + 167 + 160 + 165

9

=164.6cm

*(not shown in the conversion table and thus values for percentage fats are taken for totals 95 and 85 respectively.)

Table 4: Table showing the skin fold measurements, age, body weight, amount of fat relative to body weight and height of Italian males

Biceps fold, in mm	Triceps fold, in mm	Shoulder blade fold, in mm	Pelvis fold, in mm	Total for all folds, in mm	Age, in years	% fat from conversion table	Body weight, in kilograms	Amount of fat, relative to weight in kilograms	Body Height in cm
7	15	7	8	37	17	15.5	60	9.3	170
5	7	10	10	32	17	13.7	68	9.3	181
12	16	23	20	71	19	23.3	71	16.3	175
10	20	9	11	50	18	19.0	62	11.8	168
14	17	12	18	61	17	21.4	59	12.6	166
15	13	18	22	68	18	22.8	64	14.6	174
9	15	17	24	65	19	22.2	66	14.7	169
11	19	22	19	71	20	23.3	74	17.2	184
13	18	20	15	66	17	22.4	69	15.5	172

• Average percentage fat: 15.5 + 13.7 +23.3 +19.0 +21.4 + 22.8 + 22.2 + 23.3+ 22.4

9

= 20.4%

• Average body weight: 170 + 181 + 175 + 168 + 166 + 174 + 169 + 184 + 172

9

= 173.2 cm

RESULTS

From the tables above and the calculations below each table, it is clearly visible that the Italian females have the highest percentage of body fat relative to body weight. The Kenyan males have the least percentage of body fat compared to body weight.

The Italian females have a body fat percentage of 31.7% while the Kenyan males have a fat percentage of 16.3%. This 15.4% difference which is quite big. The Kenyan females on the other hand have a body fat percentage of 29.3%. This is a 13% difference compared to the Kenyan males and a 2.4% difference with the Italian females, which is substantially small. The Italian males have a percentage of 20.4%, which is a 4.1% difference with the Kenyan males, 8.9% with the Kenyan females and 11.3% with females from their own country.

Thus, from this, we can deduce that even though the Italian females have a higher percentage, females in general have a higher percentage of fat compared to males. This difference is about 10%. This is because of their physiological differences that allow them to store fat in their breasts, waist and buttocks. The fat is important especially during child birth. The males have less fat in their body because it is mostly muscle.

In terms of height, the males had higher averages. The Kenyan ones were seen to be the tallest with an average of 178.2cm. The Italian male had an average of 173.2cm. This means that he was shorter than the Kenyan one averagely by 5cm, which is not a big difference. The Italian females had an average of 164.6cm which was the least. The average differences between them and the Kenyan and Italian males respectively are 13.6cm and 8.6cm. The Kenyan females on the other hand had an average of 167cm which compared to the Italian females is a difference of about 2.4cm which is quite small. Compared to the males, that is Kenyan and Italian, they have an average difference of 11.2cm and 6.2cm respectively.

The following bar graphs summarize the information given above.

Conclusion

In conclusion thus, from the results gotten above, it would be correct to say that Kenyan males have the least percentage of fat relative to body weight, followed by their females then by Italian males then females. The Kenyan males are also the tallest, followed by the Italian males, Kenyan females and finally Italian females.

Therefore I think that in general it would be easy to conclude that, Kenyans aged seventeen to twenty one have a lower percentage of body fat and height compared to Italians of the same age. However, the height differences were quite small and if one might allow for error, maybe they could even have the same height average. This is why, a repeat experiment would have come in handy to confirm if indeed the Kenyans are taller. The fat percentage however was big enough to be significant even though not very big for the females. Again, a repeat experiment would have come in handy here.

I find it important to say that, there was however no relation that was established between height and percentage fat. People have different physiques, some can be tall and lean, some tall and fat, others short and lean and vice versa too. It should be noted also that there is no relationship between percentage fat and weight as sometimes people with a small body weight have a high percentage of fat and vice versa.

From the results however, one cannot conclude whether the differences in height and percentage fat are due to temperature or anything else to that effect. The differences could be as a result of the lifestyle (what technology there is to ease work, food, health and so on.) However, some suggestions on how to establish the causes of the differences have been given under recommendations and modifications.

EVALUATION

Strengths

• The experiment was done on the age group seventeen to twenty one which is a small and composed of young people who are thus arguably healthy and limit the factors to be considered such as age, if they have given birth and so on.

• It is done in Nairobi, the capital of Kenya which is inhabited by generally people from all parts of Kenya. It thus allows for some representation of the whole country. The same applies when it is done in a college in Italy that has students from all over Italy.

Weaknesses and limitations

• The trimmeter that was used was not automatic but manual and therefore much estimation had to be done. This is because, it is calibrated at 5units intervals and therefore anything that falls in between has to be estimated, which obviously increased the source of error.

• There was a lot of measuring to be done, height, weight and skin fold measurements. The more they are, the more the errors increase and the accuracy decreases. The equipment used also, had large errors.

• The experiment was carried out only once and not repeated to increase its probability on being accurate; hence increasing its validity .This gives it less credibility.

• The experiment was carried out on eighteen people from each country. That is nine people from each gender. This is a small number to represent people in the age group seventeen to twenty one in an entire country.

• The two countries have regions whose temperatures vary according to position and elevation. This fact was not emphasized in the experiment to see how different positions could affect the percentage body fat and height. It was mainly assumed from the information on temperature given on the introduction that Kenya is generally hotter than Italy yet some parts of Italy are sometimes hotter than Kenya. All the same though, this assumption might be true because Kenya is hot most of the time while in Italy it is hot only during summer.

• Although the experiment gave almost conclusive results on the height and percentage fat differences it failed to show any possible reasons for this differences. Thus one was left to think of the causes for the differences, which would include food, lifestyle, temperature, health, genetic set up and so on.

• The experiment involved taking measurements from the four recognized parts of the body that is the triceps, biceps, shoulder blade and the pelvis. The last two areas caused major problems because people, especially in my country are not very comfortable with showing their naked bodies. This being a sensitive issue thus, limited me to taking measurements from my close friends as it would be very hard for me to even ask a stranger. As a result my research fails to produce a convincing conclusion representing the whole of Kenya because the people measured are from one locality therefore more or less similar.