Hunter-Gatherer Energetics and Human Obesity

In the paper

“TEE among Hadza adults was strongly related to body size, specifically fat free mass (FFM) (r2 = 0.66, n = 30, p<0.001; Table S1).”

In the paper

“Nonetheless, average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size.”

• Also stated in: § Results · plain

  “In multivariate comparisons of TEE controlling for FFM and age, Hadza women’s energy expenditure was similar to that of Western women (n = 186) and Hadza men’s TEE was similar to Western men (n = 53); lifestyle had no effect on TEE (women: F(139) = 0.18, p = 0.67; men: F(49) = 0.17, p = 0.68) (Fig. 1, Table S1).”

• Also stated in: § Discussion · plain

  “TEE among Hadza and Westerners was indistinguishable when controlling for lean mass and fat mass (common proxies for non-activity metabolic costs) despite differences in lifestyle and estimated PAL.”

In the paper

“In comparisons among individual subjects, female Bolivian farmers [13] had higher TEE than Western and Hadza women (p<0.001 both comparisons, Table 1), and farming groups (n = 3) had consistently greater TEE in population comparisons (t = 2.76, p = 0.006, Table S1) (Fig. 1, 2).”

In the paper

“In comparisons among individual subjects, female Bolivian farmers [13] had higher TEE than Western and Hadza women (p<0.001 both comparisons, Table 1), and farming groups (n = 3) had consistently greater TEE in population comparisons (t = 2.76, p = 0.006, Table S1) (Fig. 1, 2).”

What the sources say

• Not checked yetcites [13] H Kashiwazaki, 1995, Energy expenditure determined by the doubly labeled water method in Bolivian Aymara living in a high altitude agropastoral community., Am J Clin Nutr source

In the paper

“However, individual variation in daily walking distance did not explain variation in TEE.”

• Also stated in: § Results · plain

  “but TEE was not correlated with mean daily travel distance (F(28) = 0.75, p = 0.39) (Table S1).”

In the paper

“The metabolic cost of walking (kcal kg−1 m−1) and resting (kcal kg−1 s−1) were also similar among Hadza and Western groups.”

• Also stated in: § Results · plain

  “RMR for Hadza adults measured while sitting averaged 11% above predicted BMR [27], within the range of values (7–35%) reported for other populations [35].”

What the sources say

• Not checked yetcites [27] CJ Henry, 2005, Basal metabolic rate studies in humans: measurement and development of new equations., Public Health Nutr source
• Not checked yetcites [35] AN Kanade, 2001, Energy costs of standard activities among Indian adults., Eur J Clin Nutr source

In the paper

“While the Hadza likely perform traditional foraging tasks (e.g., digging tubers or chopping tree limbs for honey) more efficiently than unacculturated Westerners can [34], comparisons of activities common across cultures do not indicate that Hadza muscle and locomotor physiology inherently more efficient.”

In the paper

“In multivariate comparisons controlling for mass, height, sex, and age, body fat percentages for Hadza adults were lower than individuals from Western (U.S. and Europe) populations (F(228) = 22.72, p<0.001).”

• Also stated in: § Discussion · plain

  “Further, while Hadza differed from Western populations in body fat percentage (F(202) = 44.05, p<0.001), variation in adiposity both within and between populations was not correlated with PAL (F(207) = 0.36, p = 0.55) (Fig. 3) nor with TEE (F(209) = 3.02, p = 0.08, β = 12.06; note that the effect of TEE on adiposity, while not statistically significant, is positive in this sample).”

In the paper

“Similarly, TEE of Hadza women who were pregnant or lactating (n = 8; 1 pregnant, 7 lactating) was no different from other Hadza women (n = 9; F(16) = 0.96, p = 0.35) after controlling for FFM (Table S1).”

In the paper

“Further, while Hadza differed from Western populations in body fat percentage (F(202) = 44.05, p<0.001), variation in adiposity both within and between populations was not correlated with PAL (F(207) = 0.36, p = 0.55) (Fig. 3) nor with TEE (F(209) = 3.02, p = 0.08, β = 12.06; note that the effect of TEE on adiposity, while not statistically significant, is positive in this sample).”

In the paper

“In a multivariate analysis controlling for sex, age, and body mass, TEE among Hadza hunter-gatherers did not differ (t(155) = −0.35, p = 0.73) from populations in market economies (Fig. 2, Table S1).”

• Also stated in: § Discussion · plain

  “Despite high PAL and dependence on wild foods, Hadza TEE was similar to Westerners and others in market economies (Fig. 1, 2).”

In the paper

“In a multivariate analysis controlling for age and sex, the relationship between TEE and estimated BMR did not differ between Hadza and Western subjects (F(239) = 0.73, p = 0.39) (Fig. S3).”

In the paper

“As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners.”

• Also stated in: § Results · plain

  “Hadza men had an estimated PAL of 2.26±0.48, significantly greater than observed PAL in Western men (n = 31, PAL = 1.81±0.21) (F(43) = 13.07, p = 0.001), while estimated PAL for Hadza women (1.78±0.30) was slightly higher than that of Western women (n = 145, PAL = 1.68±0.22) (F(162) = 3.80, p = 0.05) when controlling for age (Table S1).”

In the paper

“Estimated physical activities levels (PAL, calculated as TEE/estimated BMR), suggest that Hadza adults spend a smaller portion of TEE on BMR than Westerners.”

In the paper

“Further, while Hadza differed from Western populations in body fat percentage (F(202) = 44.05, p<0.001), variation in adiposity both within and between populations was not correlated with PAL (F(207) = 0.36, p = 0.55) (Fig. 3) nor with TEE (F(209) = 3.02, p = 0.08, β = 12.06; note that the effect of TEE on adiposity, while not statistically significant, is positive in this sample).”

In the paper

“Only farming populations had greater TEE than predicted for their body size.”

• Also stated in: § Results · plain

  “In comparisons among individual subjects, female Bolivian farmers [13] had higher TEE than Western and Hadza women (p<0.001 both comparisons, Table 1), and farming groups (n = 3) had consistently greater TEE in population comparisons (t = 2.76, p = 0.006, Table S1) (Fig. 1, 2).”

What the sources say

• Not checked yetcites [13] H Kashiwazaki, 1995, Energy expenditure determined by the doubly labeled water method in Bolivian Aymara living in a high altitude agropastoral community., Am J Clin Nutr source

In the paper

“The metabolic cost of walking (kcal kg−1 m−1) and resting (kcal kg−1 s−1) were also similar among Hadza and Western groups.”

• Also stated in: § Results · boosted

  “The energy cost of walking (kCal kg−1 m−1) for Hadza adults was well within the range of values reported for Western subjects: of 20 U.S and European populations included in a recent meta-analysis of treadmill walking cost [28], 14 had mean COTmin values below the Hadza mean (Supporting Information, Fig. S1).”

What the sources say

• Not checked yetcites [28] J Rubenson, 2007, Reappraisal of the comparative cost of human locomotion using gait-specific allometric analyses., J Exp Biol source

In the paper

“Nonetheless, TEE is remarkably similar across a broad, global sample of populations that span a range of economies, climates, and lifestyles (Fig. 1, 2).”

In the paper

“The similarity in TEE among Hadza hunter-gatherers and Westerners suggests that even dramatic differences in lifestyle may have a negligible effect on TEE, and is consistent with the view [4]–[7], [16] that differences in obesity prevalence between populations result primarily from differences in energy intake rather than expenditure.”

What the sources say

• Not checked yetcites [4]–[7]
• Not checked yetcites [16] LR Dugas, 2011, Energy expenditure in adults living in developing compared with industrialized countries: a meta-analysis of doubly labeled water studies., Am J Clin Nutr source

In the paper

“The lack of correspondence between TEE, PAL, and adiposity in our Hadza and comparative samples is consistent with previous DLW studies in Western populations [36]–[38].”

What the sources say

• Not checked yetcites [36]–[38]

In the paper

“Moreover, the lack of correspondence between TEE and daily walking distance (a large component of Hadza daily activity), or between TEE and maternal status (pregnant/nursing or not), along with other investigations of forager physiology, suggest that interactions between metabolic physiology, physical activity, and the environment are more complex than often thought.”

In the paper

“Like other complex, continuous traits (e.g., stature), environment can clearly influence TEE, as is evident in the elevated energy expenditures of traditional farmers (Table 1).”

In the paper

“For example, while Western diets are certainly more sugar-rich and energy-dense than more “traditional” diets and wild foods [4], [8], [9], many hunter-gatherers seasonally consume a large portion of their daily calories as honey [10], [11] (Fig. S2), which has high concentrations of glucose and fructose [12].”

What the sources say

• Not checked yetcites [10] FW Marlowe, 2005, Hunter-gatherers and human evolution., Evol Anth source
• Not checked yetcites [11] FW Marlowe, 2009, Tubers as fallback foods and their impact on Hadza hunter-gatherers., Am J Phys Anth source

In the paper

“For example, work with Ache foragers in Paraguay has shown that levels of leptin, critical in fat sequestration, and testosterone, an anabolic hormone, are substantially lower than levels seen in U.S. adults [42], [43].”

What the sources say

• Not checked yetcites [42] RG Bribiescas, 2001, Serum leptin levels and anthropometric correlates in Ache Amerindians of eastern Paraguay., Am J Phys Anth source
• Not checked yetcites [43] PT Ellison, 2002, Population variation in age-related decline in male salivary testosterone., Hum Reprod source

In the paper

“And studies of pregnant and lactating women in traditional cultures have shown that changes in both behavior (e.g., work load) and physiology (e.g., BMR) enable them to maintain TEE at levels similar to those of their Western counterparts [44], [45].”

What the sources say

• Not checked yetcites [44] NF Butte, 2005, Energy requirements during pregnancy and lactation., Public Health Nutr source
• Not checked yetcites [45] DL Dufour, 2002, Comparative and evolutionary dimensions of the energetics of human pregnancy and lactation., Am J Hum Biol source

In the paper

“While no living population is a perfect model of our species’ past, the Hadza lifestyle is similar in critical ways to those of our Pleistocene ancestors.”

In the paper

“Our results indicate that active, “traditional” lifestyles may not protect against obesity if diets change to promote increased caloric consumption.”

In the paper

“Recent work examining the body’s complex physiological responses to dieting and weight loss [46] supports this view.”

What the sources say

• Not checked yetcites [46] P Sumithran, 2011, Long-term persistence of hormonal adaptations to weight loss., New Eng J Med source

In the paper

“Indeed, processed, energy-dense foods have been linked to insulin resistance and cardiovascular disease among Australian foragers transitioning to village life [41].”

What the sources say

• Not checked yetcites [41] K O’Dea, 1991, Westernization and non-insulin-dependent diabetes in Australian Aborigines., Ethn Dis

In the paper

“And rather than decreasing the work needed to find food, early agriculture may reflect an effort to improve food security and predictability, even at the cost of slightly higher energy demands.”

In the paper

“The greater energy demands of traditional farming lifestyles evident in this study (Fig. 1, 2) suggest that the adoption of agriculture brought with it an increased workload for Neolithic foragers.”

In the paper

“The similarity in TEE among Hadza hunter-gatherers and Westerners suggests that even dramatic differences in lifestyle may have a negligible effect on TEE, and is consistent with the view [4]–[7], [16] that differences in obesity prevalence between populations result primarily from differences in energy intake rather than expenditure.”

What the sources say

• Not checked yetcites [4]–[7]
• Not checked yetcites [16] LR Dugas, 2011, Energy expenditure in adults living in developing compared with industrialized countries: a meta-analysis of doubly labeled water studies., Am J Clin Nutr source

In the paper

“A growing body of work on mammalian metabolism is revealing that species’ metabolic rates reflect their evolutionary history, as TEE responds over evolutionary time to ecological pressures such as food availability and predation risk [49], [50].”

What the sources say

• Not checked yetcites [49] H Pontzer, 2009, Great ranging associated with greater reproductive investment in mammals., Proc Natl Acad Sci USA source
• Not checked yetcites [50] H Pontzer, 2010, Metabolic adaptation for low energy throughput in orangutans., Proc Natl Acad Sci USA source

In the paper

“To estimate BMR for Hadza subjects, we entered each subject’s body mass and height into age-specific prediction equations developed in a large sample (n = 10,552) from a geographically broad set of populations that includes populations in sub-Saharan Africa [27].”

What the sources say

• Not checked yetcites [27] CJ Henry, 2005, Basal metabolic rate studies in humans: measurement and development of new equations., Public Health Nutr source

In the paper

“As is typical among traditional-living Hadza, over 95% of their calories during this study came from wild foods, including tubers, berries, small- and large-game, baobab fruit, and honey [17] (Fig. S2).”

What the sources say

• Not checked yetcites [17] FW Marlowe, 2010, The Hadza: Hunter-Gatherers of Tanzania. Univ. California Berkeley.

In the paper

“Similarly, while high activity levels have been reported in some subsistence farming populations [13]–[15], a recent meta-analysis of 98 diverse populations worldwide found no effect of socioeconomic development – a rough index of mechanization and diet – on daily energy expenditure or activity level [16].”

What the sources say

• Not checked yetcites [16] LR Dugas, 2011, Energy expenditure in adults living in developing compared with industrialized countries: a meta-analysis of doubly labeled water studies., Am J Clin Nutr source

In the paper

“Studies such as these, as well as results here, suggest that physical activity may be only one piece of a dynamic metabolic strategy that is continuously responding to changes in energy availability and demand.”

In the paper

“While the lifestyle of late Pleistocene hunter-gatherers was no doubt highly active as seen in foragers today, our results suggest that their daily energy requirements were likely no different than current Western populations.”