Scientific Research - Introduction
15 Feb 2011
CHAPTER I - INTRODUCTION
1.0 INTRODUCTION:
Health and current statistics
The term epidemic is commonly used to describe the increasing rates of obesity in America and around the world (National Health and Nutrition Examination Survey, 2009). The importance of a healthy and balanced diet is becoming increasingly more important in the quest for disease prevention, maintaining an ideal weight and supporting optimal health. The media and scientific community are constantly rife with new research regarding health strategies for different ages and specialist populations and the steps we can take to minimise adverse health conditions as a result. The complexity of body weight regulation presents a substantial challenge to understanding the etiology of obesity and to developing strategies to treat and/or prevent it (Hill, 2006).
Current government guidelines state the two key elements to a healthy diet are eating the right amount of food for how active you are and eating a range of foods to make sure you're getting a balanced diet (Food Standards Agency, 2010). This statement becomes ever more apparent when the subject of overweight individuals is approached. The incidence of obesity, overweight individuals, poor health and lifestyle related diseases is continually on the rise, yet many individuals believe they are eating the right foods to maintain a healthy weight and good health. Roughly 46% of men in England and 32% of women are overweight (a body mass index of 25-30 kg/m2), and an additional 17% of men and 21% of women are obese (a body mass index of more than 30 kg/m2 ) (National Health Service, 2006). This percentage has doubled since the 1980's, a period where we were warned of the dangers of saturated fat and a high consumption of animal based products and as a result should increase our consumption of vegetable oils and grain based products instead of animal products (Griel, Ruder & Etherton, 2006).
In 2002, the cost to the National Health Service (NHS) of treating obesity was estimated to be between 45.8 and 49.0 million and between 945 million and 1,075 million for treating the consequences of obesity; (NHS, 2006). Interestingly in the UK, total energy intake fell by approximately 20% between 1974 and 2004, a period where the nation was increasing in size (NHS, 2006). NHS literature also states that we are eating more fruit and vegetables due to public awareness, yet the incidence of overweight individual's further increases. This attempt to eat better is supported by Serdula et al (1999) who found that at any given time approximately 45% of women and 30% of men in America are trying to lose weight, yet obesity in America has doubled in the past 20 years (Flegal, Carroll, Ogden & Johnson, 2002). More than 1000 diet books are now available (amazon.com, 2010), with many of them departing from the governments advice and fuelling public interest due to media coverage on certain success stories (Riley, 1999).
Current recommendations
Current dietary recommendations outlined by the Food Standards Agency (2010) is one rich in whole grain carbohydrates, fruits and vegetables, with a moderate amount of lean protein (10-15%), diary produce and pulses with limited amounts of fat (especially saturated fat), sugar and salt. Key emphasis for good dietary habits focus on replacing whole grains from processed grains, eat at least five portions of fruit and vegetables a day, eat a portion of oily fish once a week, cut down on saturated fats from meat, dairy, butter and lard, decrease all processed sugar from sweets and drinks, consume less than 6g of salt a day, stay active, drink 6-8 glasses of water a day and never skip breakfast. When it comes to losing weight, the Department of Agriculture and the National Heart, Lung and Blood Institute recommend decreasing calorie intake and increasing physical activity (obesity education Initiative, 1998; Dietary Guidelines, 1995). The previous guidelines for physical activity are set at 30 minutes of moderate activity on all or most days of the week. Aside from government advice the popularity of other diet regimes such as the Atkins Diet, South Beach, Zone, Weight Watchers, Slimming World and the No-Diet Diet have increased in popularity and equally have their proponents (Katan, 2009; Dansinger, Gleason, Griffith, Selker & Schaefer, 2005). Some report success with a particular diet, and some don't. So could this lead us to believe that not all diets work for one individual and that we are all different and have different nutritional requirements?
Current guidelines for nutrition and weight loss are somewhat general, and it can be argued that this is due to it being advice that has to be distributed to the mass population, anything considered more than general advice could be costly to implement, but in retrospect the current health paradigm is costing the government millions every year. Due to current guidelines being of a general nature it gives the impression that we are all the same and need the same nutritional requirements. Our culture is now very diverse with races from all over the world residing in one country. Is it right that such guidelines are the same for every individual, even if someone is born in one culture and resides in another? It would be logical to suggest that his/her nutritional requirements would be different to natives living in that country, due to what is available in certain regions of the world. Through thousands of years, cultures and colonial groups have developed eating certain food types that are available to them, for far longer that we have lived in the modern world (Eaton, 2006). The foods that we eat today are far different from the foods that we habitually ate before the wide scale farming of grain based foods (Eaton & Conner, 1985).
In the past decade, nutritional research has undergone an important shift in focus from epidemiology and physiology to molecular biology and genetics (Muller & Kersten, 2003). A diet called Metabolic Typing (MT) has recently gained increased exposure in the media and is currently a popular tool used by many private nutritionists. MT claims it can determine how you are designed to eat for your particular body type. This includes proportions of macronutrients, types of food you should and shouldn't eat and foods to avoid in maximising weight loss and balancing homeostasis on multiple levels (Wolcott & Fahey, 2000). MT seems like a logical step in the right direction, yes it is more specific, more time consuming, costly, and more challenging to adapt to, but shouldn't nutrition be specific to the individual? We are all different on a cellular level just like our individual fingerprints, so can we justify an individualised approach to nutrition in context of the whole population in an effort to optimise the national health status. After all food isn't just a fuel for daily life, food and its nutrition aims to fine tune many biochemical processes such as transport mechanisms, interactions between metabolic pathways, regulate hormone function and rebuild damaged and diseased tissue (Ordovas & Vincent, 2004).
The rationale behind this research into individualised nutrition through the process of MT, is to identify the impact on health, weight loss and overall well-being in comparison to the current recommended dietary guidelines for health. Many diets have been analysed in past resereach for the their effectiveness in eliciting weight loss and greater levels of health, but none have ever explored the individualised approach. In retrospect we are analysing the effectiveness of individual dietary guidelines in comparison to the current "one size fits all" approach to nutrition that current diet regimes that exist. Such results have the ability to have a profound effect on the way we view the body and its nutritional requirements and such results could pave the way for further research into the area of personalised nutrition.
CHAPTER II - REVIEW OF THE LITERATURE
2.0 - REVIEW OF THE LITERATURE:
The Calorie Equation
For the most part combating obesity through weight loss is the metabolic consequence of a reduced caloric intake (Griel, et al, 2006; Hill, 2006). The recommended calorie intake will depend on age, activity level and body mass, but for the average male intake should be 2500 Kcal, and 2000 Kcal for females, with a reduction of 500 Kcal if weight loss is the goal (NHS, 2009). Although the energy balance equation may be biased, overfeeding for example produces much less compensatory change in energy expenditure than food restriction (Hill, sparling, shields & Heller, 1987 & Heyman et al, 1992). In essence, our biology is geared to protect more strongly against weight loss than against weight gain (Hill, 2006).The literature suggests that the types of food are not important in terms of weight reduction when calories are evenly maintained (Pelkman et al, 2000). Similar weight and body fat loses have been observed when calories are evenly maintained below baseline energy requirements between low and high fat diets (Golay et al, 1996; Kinsell et al, 1964; Garrow, 1981). A substantial body of evidence indicates that all human and animal organisms have biological systems and metabolic processes that help match energy expenditure with intake and thus maintain body weight (Hill, 2006). Ultimately reduction in energy intake produces a decline in energy expenditure (Hill, 1987; Heyman et al, 1992). Mayer, Purnima & Mitra (1956) states that individuals with high energy expenditure due to high levels of daily exercise were better at regulating energy intake than low daily exercisers due to bio-regulatory mechanisms.
With the diet energy balance in discussion it is important to address the energy expenditure element in weight maintenance. Basset, Schneider & Huntingdon's (2004) research found that Amish men walk 18,000 steps per day and women 14,000 steps per day. Whereas the research of Brown, Williams, Ford, Ball & Dobson (2005) found inhabitants of Colorado, USA, walked only 6733 steps for men and 6384 for women which leads to a difference in calorie expenditure between 400-600 kcal a day and shows an approximate idea of how much our general lifestyle has changed over the decade as modern living has emerged. From limited data available it is evident that energy intake has increased in comparison to energy expenditure, thus leading to weight maintenance issues across modernised populations (Hill, 2006), a somewhat likely contribution to the current obesity epidemic. But exercise is not the key answer, diet is the key element in the health and diet equation as studies demonstrate no or modest weight loss with exercise alone (Bensimhon, Kraus & Donahue, 2006; Curioni & Lourenco, 2005). Evidence has shown that humans in general are drawn to high calorie energy dense foods usually with a sweet taste (Drewnowski, 1998), hinting at a strong biological drive to store energy and reduce levels of physical activity (Hill, 2006). Hill (2006) hypothesises that entire populations are not obese as a result due to individuals being able to oppose these environmental factors and conscious efforts to avoid such calorific foods.
Literature on Previous Diet Comparisons
Shai et al (2008) states that as a whole dietary research comparing the effectiveness and safety of weight loss diets are frequently limited by short follow up times and high dropout rates and as of yet no research is available on diet effectiveness at five to ten year periods. McLaughlin (2006) found a diet moderately lower in carbohydrate and higher in unsaturated fat is as efficacious as the traditional low-fat diet in producing weight loss and possibly be more beneficial in reducing markers for cardiovascular disease. Hu (2005) found that higher protein diets increase short term weight loss and improve blood lipids, but long term data is lacking. Garg et al (1994) found high carbohydrate diets compared with high monounsaturated fat diets cause persistent deterioration of glycemic control and accentuation of hyperinsulinemia, as well as increased plasma triglyceride and low-density lipoprotein cholesterol levels. This may not be desirable, especially as low carbohydrate diets improve cardiovascular risk factors, lipid risk factors and blood pressure (de Souza, swain, Appel and Sacks, 2008), all very favourable outcomes. Stern (2004) found weight loss at 1 year between a conventional diet and a low carbohydrate atkins style diet to be non significant but effects of atherogenic dyslipidemia and glycemic control to be still more favourable as seen in other research with low carbohydrate diets. However Aude et al (2004) found a diet higher in protein and monounsaturated fat in comparison to the recommended dietary guidelines elicited twice as much weight loss as well as lipid favouring effects.
One of the largest diet comparisons comparing macronutrient ratios found all diet combinations to be as effective as one another at one year and one year follow up (Sacks, 2009). Although fat and carbohydrate content differed substantially in the respective diets, protein content only fluctuated by 10%, with the greatest protein content being 25%, still relatively low in comparison to Atkins, some MT diets and the Paloe diet. Shai (2008) found participants who stuck to and completed their trial lost on average 3.3 kg on a low fat diet, 4.6kg on a Mediterranean diet and 5.5kg on a low carbohydrate diet indicating more favourable results on higher fat or higher protein approaches to weight loss and management. Increases in whole grain carbohydrates are recommended as part of a healthy lifestyle (Salmeron, Asherio & Rimm, 1997), but Jenkins et al (2008) found a high-cereal fibre diet to decreases levels of good cholesterol, whereas a lower glycemic index approach increased levels of good cholesterol (Ford & Lui, 2001; Frost et al, 1999).
Many diets have proven the efficacy of higher protein and fat diets as being more or as effective as lower fat high carbohydrate diets (Sharman, Gomez, Kraemer & Volek, 2004; Aude, et al, 2004), yet few have concluded its implementation as a dietary solution and even fewer studies have concluded on the benefits to health. Many studies have identified that higher protein and fat diets decrease levels of plasma triglycerol, CVD risk factors and LDL cholesterol (Samaha, Iqbal & Seshadri, 2003; Mcauley, Hopkins & Smith, 2005), yet none conclude the evidence is enough to make a shift towards this health promoting dietary method. One key factor all research points too, is that a period of calorie restriction produces significant weight loss over the first 1-2 weeks (Heymsfield et al 2006; Forbes, 1970), which rationally comes from a stage of restriction, but then is always followed by a period of adaptation (Heshka, Anderson & Atkinson, 2003; Torgerson, Hauptman, Boldrin & Sjostom, 2004). Although weight loss seems not significant over long periods of time between diets it is evident higher protein and fat diets create better health profiles.
Efficacy of High Protein Diets & Saturated Fat
High protein, high fat diets have drawn much controversy in recent years as well as much popularity in the weight loss and scientific research communities for their effectiveness in short term weight loss and positive effects on many health parameters (Garg et al, 1994; McLaughlin et al, 2006; Hu, 2005). Reduction of carbohydrates and increases in fat and protein in diets such as the Atkins is thought to increase satiety, facilitate weight loss and improve cardiovascular health (Hu, 2005). Although higher protein diets increase short term weight loss (Baba et al, 1999; Brehm, Seeley, Daniels &D'Alessio, 2003), longer term evidence of the overall health benefits is lacking (Hu, 2005). Over six months a high protein diet in comparison to a low protein diet enabled participants to lose significantly more weight (5.8 vs 1.9 Kg; P=0.002), although weight loss was insignificant at the 12 month mark (Stern, Iqbal, Seshadri, Chicano, Daily, McGrory, Williams, Gracely & Samaha, 2004). The rationale for carbohydrate restriction is that changes in glucagon and insulin concentrations will enable the body to effectively oxidise fat as fuel rather than store it (Westman et al, 2007). Many positives regarding high protein intake are evident, but what about the negatives?
High meat consumption has long been associated with increased disease status, especially red meat consumption (Gregor, Toman & Prusova, 1971; Bingham, Hughes & Cross, 2002). This advice is supported by the association in humans regarding saturated fat intake and coronary heart disease (CHD) risk (Kato, Tillotson, Nichaman, Rhoads & Hamilton, 1973; Keys, Aravanis & Blackburn, 1966). This is often the case with high meat diets as meat and dairy along with many highly processed foods contain the highest quantities of saturated fat in many people's diets (NHS, 2010). But recent epidemiological studies have shown positive (Ascherio et al, 1996; Boniface & Tefft, 2002), inverse (Gillman, Cupples, Millen, Ellison & Wolf, 1997; Mozaffarian, Rimm & Herrington, 2004) or no (Kushi, Lew & Stare, 1985; Tucker et al, 2005) associations of dietary saturated fat and CHD mortality. It is evident many earlier, possibly outdated, studies have associated links between saturated fat and CHD, more recent studies have revealed otherwise. Hunt, Gallagher, Johnson and Lykken (1995) actually found high meat consumption to increase mineral uptake such as zinc. The omni-protein diet research paper, found the south beach and zone diets, which were high in protein, generally consistent with the national recommendations of intakes of saturated fat, fibre and cholesterol; however concerns were raised over the Atkins diet due to its high saturated fat content. Post study meta analysis on the Atkins diet later revealed it's positive effect on weight loss and HDL cholesterol for people with or without the metabolic syndrome (Souza, Swain, Appel & Sacks, 2008).
Increasing protein content has also been shown to decrease CVD risk factors (Souza et al, 2008), and positively affects blood pressure, lipid risk factors and CHD (Appel, Sacks & Carey, 2005). Although increasing protein does increase saturated fat and cholesterol intake, it is universally accepted from past research that replacing carbohydrate content with saturated fat causes a reduction in total and low density lipoprotein (LDL) (Ginsberg et al, 1990; Berry et al, 1992; Baggio et al, 1992; Grundy, Florentin, Nix & Whelan, 1988; Colquhoun, Moores, Somerset & Humphries, 1992; Mensink, 1989; Kris-Etherton et al, 1999; Lopez-Segura et al, 1996). Dr Rosedale (2009) states that concerns regarding cholesterol have been wrongly placed, and that cholesterol is not the major culprit in heart disease, or any disease, only oxidised cholesterol can irritate and inflame tissues, but this is the case with any fat, even anti-inflammatory omega three fats. Dr Rosedale states that sugars such as glucose and fructose's infliction on the lining of arterial tissues is a major player in inflammation and resultant arterial plaque build up.
Dayton, Pearce & Hashimoto (1969); Leren (1970); Turpeinen et al (1979) showed that reduced fat intake did not positively affect CVD risk factors, but instead the ratio of saturated fat to polyunsaturated fat, a hypothesis recently supported by Jackobsen, O'Reilly & Heitman (2009). Although the strong heart study revealed positive associations between saturated fat and CVD in younger adults, these results were non-significant after adjustment for the polyunsaturated, monounsaturated and trans fat intake (Xu, Eliat-Adar & Loria, 2006). In contrast to this, and more importantly for consumer health, a multitude of studies showed no link between saturated fat intake and CHD including, the Western Electric Study (Shekelle, Shryrock & Paul, 1981), the Hololulu Heart study (McGee, Reed, Yano, Kagan & Tillotson, 1984), the Ireland Boston Heart Study (Kushi, Lew & Stare, 1985), the Caerphilly Study (Fehily, Yarnell, Sweetnam & Elwood, 1993), the Framlingham Heart Study (Posner et al, 1991), the Israeli Ischemic Study (Goldbourt, Yaari & Medalie, 1993), the Alpha-Tocopherol Beta-Carotene Study (Pietinen, Ascherio & Korhonen, 1997), the Nurses' Health Study (Oh, Hu, Manson, Stampfer & Willet, 2005), the malmo Diet and Cancer Study (Leosdottir, Nilsson, Nilsson & Berglund, 2007) and the Baltimore Longitudinal Study of ageing (Tucker et al, 2005).
Macronutrient Effect on Mood, Psychology, Well-Being, Blood Glucose Level and Blood Pressure
Many studies conducted found adherence was an important determinant of weight loss regardless of the diet (Hu, 2005). Dietary adherence brings personal psychology and lifestyle traits into the equation which could unfold to be a demining factor in any study. After all any individual has the power to do whatever he or she wants, only themselves will hold themselves back. It can be argued that relatively minor changes in mood will be amongst the first symptoms of a poor diet (Benton, 2002). It is evident poor diet affects almost all physical and mental functions, but to what degree in different diets needs to be identified. McClernon, Yancy, Eberstein, Atkins, & Westman (2005) found that a low carbohydrate ketogenic diet had more favourable effects on hunger and general outcomes compared with a low fat diet and concluded this could be down to short term greater weight loss, but found diet improvements in general improved mood on multiple levels.
Other research has shown profound changes in what researchers considered "protein cravers and carbohydrate cravers" and their feeling before and after a protein or carbohydrate rich meal. Christensen & Pettijohn (2000) found that protein cravers reported feeling anxious or hungry prior to their cravings and happy, normal, bored, and energetic following protein-rich food consumption. A non-significant correlation existed between "protein" cravers' ratings of craving intensity and mood, but a significant positive correlation existed between "carbohydrate" cravers' ratings of craving intensity and almost all mood scales assessed for both male and female "carbohydrate" cravers. This could indicate an example of biochemical individuality and how we respond to favoured food groups and our natural tendencies towards specific food groups. Hirdes (1993) indicates that coming from a background of high socioeconomic status with relatively high levels of income and education, not smoking and moderate alcohol use are all associated with good health. Belloc & Breslow (2004) also feel high socioeconomic status leads to long term good practices in health, independent of age, sex and economic status due to a generally more positive psychological outlook.
Blood Pressure is an outside variable in many scientific studies due to so many factors influencing it, including diet, exercise, sodium levels, cardiovascular health & blood viscosity (Rasmussen et al, 1993). Rasmussen et al (1993) found a diet rich in monounsaturated fat found reduced daytime systolic (131 +/- 3 vs. 137 +/- 3 mmHg, P < 0.04) and 24-h systolic blood pressure (126 +/- 8 vs. 130 +/- 10 mmHg, P < 0.03) as well as daytime diastolic (78 +/- 2 vs. 84 +/- 2 mmHg, P < 0.02) and diurnal diastolic blood pressure (75 +/- 6 vs. 78 +/- 5 mmHg, P < 0.03) as compared with a high-carbohydrate diet. In general, positive dietary changes reduce blood pressure (Appel et al, 1997; Jürgens & Graudal, 2008; Rouse, Armstrong, Beilin & Vandongen, 1983), as well as reductions in body weight. The influence of blood glucose from dietary changes has been well documented, which spurred the introduction of the low Glycemic index and low Glycemic load diets with interest in the effect of various types and amounts of dietary carbohydrates and proteins on blood glucose (Gannon & Nuttall, 2004).
Rasmussen et al (1993) found evidence of lowered blood glucose levels on the high-monounsaturated diet compared with a high-carbohydrate diet, with lower fasting blood glucose (6.1 +/- 0.3 vs. 6.8 +/- 0.5 mM, P < 0.05), lower average blood glucose levels (7.4 +/- 0.5 vs. 8.2 +/- 0.6 mM, P < 0.04), and peak blood glucose responses (9.9 +/- 0.6 vs. 11.3 +/- 0.7 mM, P < 0.02). Samaha et al (2003) found fasting plasma glucose levels in patients on a low-carbohydrate diet decreased from 9.32 mmol/L (168 mg/dL) to 7.88 mmol/L (142 mg/dL) after 6 months in comparison to a low fat diet. Gannon & Nuttall (2004) found their high protein diet to maintain blood glucose levels at 7.6 ± 0.3 mmol/L and 9.8 ± 0.5 mmol/L in the higher carbohydrate diet. Ultimately, dietary carbohydrate percentage in comparison to protein and fat hold significant influence over the blood glucose levels of an individual during daily living. Although research linking cholesterol to heart disease appears inconclusive, research on elevated blood glucose levels and CVD risk factors seem highly correlated. Research shows that individuals, with and without diabetes, who have elevated blood glucose levels have increased susceptibility to developing heart disease and CVD (Dunder, Lind, Zetheluis, Berglund & Lithell, 2003; Saydah et al, 2001; Qiao et al, 2004; Temelkova-Kurktschiev et al, 2000; Balkau et al, 1998; Liu et al, 2000; Levitan, Song, Ford & Liu, 2004; Danaei, Lawes, Vander Hoorn, Murray, & Ezzati, 2006; Wei, Gaskill, Haffner & Stern, 1998; Rodriguez et al, 1999; Vaccaro, Ruth & Stamler, 1992; Lowe et al, 1997).
Danaei et al (2006) also found that data collected showed 1,490,000 deaths from heart disease and 709,000 deaths from stroke were directly related to elevated blood glucose levels, which compared to the number of deaths seen from smoking. Rodriguez et al (1999) and Vaccaro et al (1992) noted a liner progression with increasingly elevated blood glucose levels and the risk of CVD and heart disease. In our modern diet this could attributed to the UK diet now containing on average 507g of starchy carbohydrates, whereas in 1987 this intake was closer to 236g (National diet and nutrition survey, 2003). It seems obvious that maintaining an even blood glucose level during waking hours is paramount to energy production and reduced risk of many onset diseases. Seeing as 10mmol/l is high and around 2-3mmol/l is low, we would look for glucose level to stay stable at 4-6mmol/l daylong (Ludwih, 2002).
Dr Rosedale's Work & Palaeolithic Nutrition
Diet is a widely debated topic, should we eat all food in moderation, or are there foods that should not be in our diet at all if we want optimum health? Dr Rosedale (2010), from his research believes that our diet should contain very minimal amounts of grains (sprouted only), no sugars, moderate amounts of avocado, nuts, seeds, butter, ghee, eggs, coconut, olive and saturated animal fat, ample animal and fish protein, no safflower, sunflower, soyabean, trans, sesame or corn oil, moderate amounts of dairy as well as ample fruit and vegetables. This noticeably contradicts current nutritional guidelines which outlines ample intake of whole grains, fruits and vegetables, minimal amounts of saturated fats, the limited fat intake should be from vegetable oils such as olive, sunflower, canola and margarine, moderate amounts of lean animal and fish protein, minimal sugars, salt and processed goods, and moderate low fat only dairy (Food Standards Agency, 2010). Dr Rosedale Oneness Diet almost mirrors the general guidelines for dietary intake in the The Metabolic Typing Diet (before it moves into individual macronutrient ratios), which looks more toward a traditional or Palaeolithic approach to nutrition. Foods such as cereal grains, dairy, refined sugars, refined vegetable oils and alcohol would have been unavailable during preagricultural hominin period but now makes up 72.1% of the modern American diet (Cordain, 2000), a diet that is very similar of the UK and many other developing countries. Maybe we should be looking to the past for nutritional answers seeing as looking forward has only created greater incidences of obesity, heart disease, cancer, diabetes and many other lifestyle related disorders (Westerman, 2007).
Ancestral Diets & Palaeolithic Nutrition
Estimates from Eaton (2006) suggest that ancestral dietary energy intake comprised of 35% fat, 35% carbohydrate and 30% Protein, saturated fat 7.5% of total fat, omega 6:3 ratio at 2:1 and cholesterol at 480mg/d. Seeing as recent reports question the superiority of low fat diets (McLaughlin et al, 2006), we need to look to past dietary research for answers and future direction. In comparison of western and pre-agricultural diets the latter was relatively low in carbohydrate (Eaton & Konner, 1985; Eaton, 2006). For example, in North America before migration, a traditional diet consisted of wild plants, meat, fish and berries (Westman et al, 2007; Eaton, 2000). Eaton (2000) goes on to explain how ancestral diets would have been completely absent of refined sugars, cereals and dairy products, yet high in fibre and nutrients from fruit and vegetables with a strong protein profile, absently seen in the modern diet.
After the late 1800's, where a change in lifestyle occurred, many health problems were extensively documented as a result (Hildes & Schaefer, 1984; Schaefer, 1973; Shephard & Rode, 1996), with specific emphasis on the introduction of sugar and flour as the causative factor. Ethnographic and anthropological studies of hunter-gatherers conducted in the 19th and 20th centuries identified that no single, specific diet would have typified the nutritional intake of all pre-agricultural human populations (Cordain, Eaton, Miller, Mann & Hill, 2002). Many people do not know their ancestral eating pattern, something metabolic typing identifies (Wolcott & Fahey, 2000). It is this identification of hunter gather diets that may be invaluable in creating therapeutic diets that reduce the risk and onset of cardio vascular disease (CVD) in westernised countries (Cordain et al, 2002). It is questionable whether the human genome has changed enough to accommodate the western diet, so in essence it is hypothesised by many, that genetically, humans remain adept to a Palaeolithic dietary regime (Eaton, 2000).
There is growing awareness that the profound changes in the environment (e.g. diet and other lifestyle conditions) that began with the introduction of agriculture and animal husbandry (≈ 10,000 years ago), occurred too recently on an evolutionary scale for the human genome to adjust (Cordain et al, 2005). The persistence of an obesity epidemic and type two diabetes suggests that new nutritional strategies are needed if the epidemic is going to be overcome (Westmanet al, 2007). Analysis of modern food consumption and its relation to obesity and diabetes, found the increase in calories entirely due to an increase in carbohydrate consumption (Morbidity and mortality weekly report, 2004). Given this finding, it is reasonable to postulate that diets that reflect a more Palaeolithic nutritional profile may be as healthy as, or even healthier than, the current high carbohydrate recommendations of the modernised diet (Westman et al, 2007).
Metabolic Typing, Biochemical Individuality & Individualised Nutrition
It is impossible to currently compare the effectiveness of MT in comparison to other diets, let alone a low fat diet, as current research in this area is non-existent. Individualised nutrition is an emerging concept in science and practice, and the only research in this area is nutrigenomics and nutrigenetics. Research such as Cordain et al (2000), Eaton (2006) and Cordain et al (2002) indicates that there would have been no single universal diet consumed by all extinct homini species, diets would have varied by geographical locale, climate and specific ecologic niche. MT in essence identifies biochemical individuality just as ancestral human would have eaten centuries ago across multiple cultures. For example arctic populations consume >60% fat whereas more tropical populations consume only <25% fat (Cordain et al, 2000). Many current diet studies draw equal conclusions between diets such as the Ornish, Atkins, South Beach and Weight Watchers diets (Eckel, 2005), this possibly due to biochemical individuality and a need for personal nutrition when it comes to adopting dietary choices. Possibly the reason we commonly see as many failures as successes in many dietary studies (Sacks et al, 2009).
For whatever reason it seems apparent that individuals are different on many genetic, biochemical and metabolic levels due to many factors such as your autonomic nervous system, oxidative system, individual physical structure and ancestral heritage. It is commonly taken for granted that human beings are very different on an external level, with respect to hair colour, skin colour, features, skeletal and muscle structure, but we are largely inattentive to the biological diversity that exists internally (Wolcott & Fahey, 2000). Shai (2008) concluded as an outcome of their large two year trial between popular diets that personal preferences and metabolic considerations might inform individualised tailoring of dietary interventions. Williams's book Biochemical Individuality (1998), looks at the biology of individuals and how this effects dietary needs. He states that characteristics that an organism inherits are an implication of hereditary and environment, if we make false implications that characteristics are inherited then we make false implication that environment has nothing to do with human evolution. Eckel (2005) states it is more than plausible that the right diet needs to be matched with the right patient, this could be possible with investigation into nutrigenomics.
Nutrigenomics and Nutrigenetics
There is widespread disagreement among dietary experts about what we should be eating, and it is virtually impossible to make sense of the cacophony of conflicting opinion (Wolcott & Fahey, 2000), it seems virtually all dietary experts have a one-size fits all dietary solution. It seems more that plausible that for maintenance of reduced body mass, the right diet needs to be matched with the right individual, ultimately a "nutrigenomics" approach, where diet can be matched to individual genotypes (Eckel, 2005). Nutrigenomics explores the effects of nutrients on the genome, preteome and metabolone, and nutrigenetics aims to elucidate the effect of genetic variation on the interaction between diet and disease (Oordovas & Mooser, 2004). Nutrigenomics considers the relationship between specific nutrients or diet and gene expression and, it is envisaged, will facilitate prevention of diet-related common diseases (Chadwick, 2004).
Nutrigenomics and nutrigenetics in the longer term will lead to personalised dietary recommendations like the MT diet, but from a valid scientific perspective. Nutrigenomics is an emerging science with only very recently published data not available for reference, the only reference material is that of recent media coverage of the unpublished studies. Recent results at an American Heart Association conference found that those on a diet which matched to their genotype lost 2-3 times more weight over twelve months compared with those on the "wrong" diet for their genotype (BBC News, 2010). This is a startling study in personalised nutrition and uncovers the potential of nutrigenomics, nutrigenetics and MT. Recent yet also unpublished results at the school of nutrition and health sciences at Taipei Medical University found that no matter what gender or metabolic type used the diet, there was significant weight loss, fat-loss and waistline reduction (p<0.05) with all participants.
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