Can Energy-Restricted Diets Help in Controlling Obesity? Essay (Article)

Abstract

Fighting obesity has been an ongoing battle that still haunts mankind. Despite being aware of the fact that the ingredients of our daily meals have a great impact on the structure and functioning of our bodies, we care very little about such aspects. It is not until we become victims of obesity that we start controlling our diets. In line with previous research in this field, this paper tries to assess the effects of energy-restricted diets on obese postmenopausal women. 680 free-living, post-menopausal women took part (from 2005 to 2012) in this research. Depending on their waist size, the participants were divided into two groups.

Among these participants, 560 were found to have a waist size of ≥ 90 cm. To notice the effect of an energy-restricted weight loss diet on these obese women, they were divided into two groups of 280 each. One group was selected for an 18-month energy-restricted diet. Various tests were done to measure the biomarkers for cardiovascular disease (CVD) and risks of breast cancer. The results showed a considerable reduction in the waist size of the participating women. In addition to the weight loss, it was also noticed that the women showed fewer indications of cardiovascular diseases and breast cancer.

Discussion

Since the past couple of decades, obesity has become a menace for people, health care professionals, and governments of industrialized nations. It is gaining rapid pace in the developing nations as well.¹⁰ It is the need of the hour to devise measures to tackle this multifaceted ailment. Several types of research have been done in the past to arrive at certain concrete results that might suggest some remedies for reducing the causes of obesity.

This particular research is a step towards assessing the effectiveness of an energy-restricted diet on obese menopausal women. The finally selected 280 participants were subjected to oral glucose tolerance tests (OGTT), after a fasting period of 16 hours. To determine the plasma glucose levels in the participants, blood samples were taken after 0, 15, 30, 60, 90, and 120 minutes – after glucose (@ 1 g/kg) was administered to them. “The normal fasting plasma glucose level was recently defined as less than 100 mg per decilitre (5.55 mmol per liter).”¹⁶

The OGTT test showed that there was a considerable improvement in the glucose tolerance levels of the participants after 18 months of intervention. The insulin concentration showed a decrease over the period whereas, the glycated hemoglobin remained unchanged. The biomarkers about CETP activity, free fatty acids, ApoB, and cortisol showed a downward trend. In contradiction, the biomarker about ApoA1 showed significant improvement.

An ultrasensitive mouse insulin enzyme-linked immunosorbent assay kit was used to measure the insulin levels of the participants. This kind of assay kit is the most commonly used method for determining insulin levels. Further, the inflammatory biomarkers for breast cancer risk were analyzed, using frozen stored plasma or serum samples. The tests were done on the healthy weight control group and the overweight intervention group. The results showed that there was no change in the biomarker concentrations in the control group throughout the study. On the contrary, the biomarker concentrations showed considerable changes in the overweight pre-intervention group.

In addition to the aforementioned results about CVD and breast cancer risks, the energy-restricted diet showed considerable improvement (reduction of waist size) in the overweight control group (with special dietary support). The overweight group with no special dietary support did not show any change in the waist size. Table 2 depicts the detailed results of tests conducted on the control group (waist circumference ≤ 80 cm), pre-intervention overweight group, and post-intervention overweight group (waist circumference ≥ 90 cm).

Whereas the biomarkers about the control group showed no changes throughout the study, there were significant changes in the overweight group. IGF-1 (ng/ml) decreased from 430 to 170, IL-6 (pg/ml) decreased from 0.89 to 0.71, CRP (µg/ml) decreased from 1.15 to 1.00, and TNF-α (pg/ml) decreased from 1.21 to 1.05. PAI-1 (ng/ml) decreased from 3.44 to 3.15, VEGF (pg/ml) decreased from 100 to 70, Leptin (ng/ml) decreased from 4.25 to 3.35, and Resistin (ng/ml) decreased from 3.50 to 3.00. The only exception was Adiponectin (µg/ml) which increased from 1.35 to 2.30. The p-value pertains to the comparison of the post-intervention concentration of biomarkers in the overweight intervention group and the healthy control group.

“Overweight and obesity are risk factors for several common chronic diseases.”⁷ Intake of excess carbohydrates is seen as the major factor leading to such ailments. So it is always advised to prefer fewer intakes of carbohydrates and more proteins.⁷ “An energy-restricted, high protein, the low-fat diet provides nutritional and metabolic benefits that are equal to and sometimes greater than those observed with a high carbohydrate diet.”¹²

Diets with high protein and low-fat contents have a definite effect on body weight. This is invariable of the energy intake; the energy intake sustains the organic processes that are a result of the aforementioned diet intake.⁶ Similar researches also suggest that “diets with reduced ratios of carbohydrates to protein increase weight loss, increase the loss of body fat, and reduce loss of lean tissue.”⁹ But at the same time, there are researchers who believe that even though the intake of a high protein and low-fat diet might reduce the body weight, the sustenance is not proven.⁸

Having said that, it should be understood that there are different kinds of protein and as such, their effect on the body is also different. Like, “The effects of white meat from poultry and fish are known to differ from those of red meat from beef and pork.”⁵ Therefore, dieticians should lay stress on the quantity and basis of protein.

“Overweight postmenopausal women can achieve significant weight-loss and comparable short-term improvements in body composition and lipid-lipoprotein profile by consuming either a moderate-protein (25% of energy-intake) poultry or beef-containing diet or a Lacto-Ovo vegetarian protein (17% of energy-intake) diet.”¹¹

Research conducted on New Zealanders suggested that there is a reasonable weight loss when obese people are given a high protein, fiber-rich carbohydrate, and fat reduction diet. The research also suggested that high protein diets have several other benefits other than controlling obesity.² To experience better results, a high protein diet should be combined with regular exercise. This would even help in improving “glycemic control and CVD risk markers.”¹⁷

Governments of various nations are doing their bit to tackle obesity. The European Food and Safety Authority suggests that “a food should contain a maximum of 250 kcal per serving and comply with specifications laid down in Directive 96/8/EC about food products under Article 1 (2b) of that Directive.”⁴ After a survey, it was also established that, “a cause and effect relationship has been established between the consumption of meal replacements in substitution of regular meals and the maintenance of body weight after weight loss.”⁴

It is understood that genes play a crucial role in the shape and weight of a person’s body. Does it mean that people whose parents are obese have to live with obesity, even if they follow a strict energy-restricted diet? Researches show that “Under energy restriction, TFAP2B may modify the effect of dietary fat intake on weight loss and waste reduction.”¹³

It is often believed that in addition to the energy-restricted diet, having a regular exercise routine can also prove beneficial for people suffering from obesity. But one of the researches showed that “Exercise training provided no additional benefit to following a high-protein, hypocaloric diet on markers of endothelial function in overweight/obese women with PCOS.”¹⁵ A research suggests that, “a high-dairy calcium diet does not substantially improve weight loss beyond what can be achieved in a behavioral intervention.”¹

Another common belief is that once weight loss has been achieved, it is a must to continue using the body’s generated energy otherwise there might be a risk of gaining obesity once again. One of the researches suggests that, when obese young adults were given an isocaloric diet, a weight decrease of 10 to 15 percent was observed. It was further noticed that the ‘resting energy expenditure’ and the ‘total energy expenditure’ also decreased. The REE and TEE, “were greatest with the low-fat diet, intermediate with low-glycemic diet, and least with the very low-carbohydrate diet.”³

Conclusion

It is understood that giving energy restricted diets to obese menopausal women decreases the body weight. But at the same time, it should be understood that simply by taking energy restricted diets the weight-loss cannot be sustained. Even after the weight-loss has been achieved, the women have to continue releasing their body energies. This might be achieved by exercising regularly. If the generated energy is not released, the women face the risk of becoming obese again. Therefore, a best plan for reducing obesity and sustaining the weight loss is to follow an energy restricted diet, coupled with regular exercise.

Research Translation

If human blood has more fat, it is harmful for the heart. Low fat dairy products have proved to be beneficial for human heart. Low fat dairy products help reduce the blood pressure and cholesterol. Calcium, Vitamin D, and potassium contained in dairy products increase the body’s “good” cholesterol, while decreasing the bad one.

One may wonder as to what are good and bad cholesterols. Well, actually there are two kinds of cholesterol present in human body. These are the ‘High Density Lipoprotein’ also referred as the HDL and the ‘Low Density Lipoprotein’ also referred as the LDL.

High density lipoprotein is considered to be better than the low density lipoprotein. It has already been determined that about a quarter of the total blood cholesterol is lugged by the high density lipoprotein. HDL is referred to as being good cholesterol because of its remedial powers with regard to human heart. Sufficient quantities of HDL (60 mg/dL) prevent heart from getting any ailments such as heart attacks. But on the other side, if the level of HDL drops to less than 40 mg/dL, it may be a risky affair because it may cause heart disease. There are certain experts who believe that HDL is more likely to tug cholesterol to the liver and removes surplus cholesterol from the plaque in arteries. This retards the speed of formation of plaque.

The low density cholesterol is not considered to be a good one. When there is excess flow of LDL in the blood streams, it may result in deposition in the arteries. The recommended level of LDL is less than 100 mg/dL. In case the LDL is higher than 100 mg/dL, it should, in no circumstances, exceed 150 mg/dL. LDL mixes with other matter and forms a rigid and substantial deposition inside the blood vessels. This may result in the inner diameter or the opening of the arteries becoming less and a time comes when that particular artery is totally blocked. The arteries even become less flexible. The outcome situation is normally referred to as ‘Atherosclerosis’ and this is when heart ailments start.

In order to keep the levels of LDL under control and within the recommended limit, people should maintain an active life style at the first place. Secondly, the daily diet should have less cholesterol and more of fibre.

Apart from the HDL and LDL, there are two more substances that might have an ill effect on the human heart. These are ‘Triglycerides’ and ‘Lp(a) cholesterol’. Just as yoghurt is good for skin whereas other dairy products are harmful, similarly there is a difference in cholesterol contents among different dairy products. Tholstrup claims that both milk and butter have more cholesterol than cheese.¹⁴

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