b********n
发帖数: 38600 | 1 Study: Junk Food more Deadly than War, Famine, Genocide
Researchers reveal disturbing numbers
http://naturalsociety.com/study-junk-food-deadly-war-famine-gen
Food in the end, in our tradition, is something holy. It’s not about
nutrients and calories. It’s about sharing. It’s about honesty. It’s
about identity. ~ Louise Fresco
You may already know that junk food is bad for your health, but you may not
realize how bad it can be. A new study from the School of Medical Sciences
at Australia’s University of New South Wales points to profound brain
changes that junk food causes, making a junk food habit “more deadly than
war, famine, and genocide”.
Say what? Yep, the food war is real, and though the UNSW study was conducted
on rats, the brain changes observed matter to us humans. As mammals we
share similar brain functioning in the orbitofrontal cortex, the part of our
gray matter responsible for sensing and evaluating the pleasurable aspects
of food.
Makers of junk food know it is highly addictive, but the UNSW study proves
unequivocally that junk food alters behavior by causing near-permanent
changes in the brain’s reward circuiting, an alteration that can trigger
obesity.
The study abstract concluded:
“We observed that rats fed a cafeteria diet for 2 weeks showed impaired
sensory-specific satiety following consumption of a high calorie solution.
The deficit in expression of sensory-specific satiety was also present 1
week following the withdrawal of cafeteria foods. Thus, exposure to
obesogenic diets may impact upon neurocircuitry involved in motivated
control of behavior.” | b********n
发帖数: 38600 | 2 http://journal.frontiersin.org/article/10.3389/fpsyg.2014.00852
Introduction
Access to highly palatable and calorically rich foods is a major
contributing factor to the increasing rates of obesity worldwide (Caballero,
2007). Eating is essential for survival and is underpinned by the
fundamental physiological need to consume energy. However, our basic
requirements for nutrients and energy to maintain physiological homeostasis
are often exceeded by an abundant source of readily available and convenient
sources of foods and drinks. Consumption beyond basic homeostatic needs,
purely based on the rewarding properties of palatable foods, is proposed to
be a central contributor to the current worldwide obesity epidemic (Berthoud
, 2004).
A range of animal and human data demonstrates that excessive consumption of
palatable food leads to changes in the sensitivity of brain reward
circuitries. These reward pathways are highly conserved across species and
have been associated with altered responsiveness to reward (e.g., food) in
obesity. Studies have demonstrated diminished responsiveness to perform food
motivated behaviors and rewarding intracranial self-stimulation in obese
rats (Volkow and Wise, 2005; la Fleur et al., 2007; Pickering et al., 2009;
Johnson and Kenny, 2010) and reduced sensitivity to reward (measured by
ratings of motivation and pleasure derived from engaging in rewarding
behaviors) in obese humans (Davis et al., 2004).
Reward-based feeding, or eating for pleasure, can be prompted by learning
that certain highly palatable foods are associated with discrete cues.
Studies using functional brain imaging in obese subjects show that palatable
foods and food-associated cues increase activity in cortical regions
associated with motivational control and reward-based feeding including the
orbitofrontal cortex (OFC), insula, amygdala, hypothalamus, striatum, and
midbrain regions including the ventral tegmental area (VTA; Wang et al.,
2001; Stice et al., 2008; Martin et al., 2010).
It has been proposed that sensitivity to cues predictive of food reward is
increased in obesity (Stice et al., 2008), and may modulate the associative
properties of food-related cues, evoking cravings for particular foods,
triggering over-consumption (Meule et al., 2012; Jastreboff et al., 2013;
Meule et al., 2014). Reducing the incentive value of a particular food
associated with an operant response or a conditioned stimulus (CS) by
lithium-induced devaluation, or pre-feeding to satiety decreases performance
of particular responses (Dickinson et al., 1996; Balleine and Dickinson,
1998; Reichelt et al., 2011, 2013). Recently, rats ingesting a sucrose
solution or a high fat/high sugar solution were shown to demonstrate
impairments in outcome devaluation in an operant setting (Kendig et al.,
2013; Furlong et al., 2014), indicating that consumption of high-energy
foods can induce differences in reward-oriented instrumental behavior. This
value driven control of responding has also been observed in a Pavlovian
setting, whereby rats will reduce food seeking (goal-tracking or magazine-
approach) behaviors associated with presentation of a CS whose associated
unconditioned stimulus (US) has been separately devalued (Pickens et al.,
2003, 2005; Ostlund and Balleine, 2007; Johnson et al., 2009; Lelos et al.,
2011). These results suggest that the motivational value of a palatable
outcome can control the performance of food seeking behaviors and if these
associations are maladaptive, cues may promote responding regardless of
whether the food is valued, so evoking over-eating. Another notion is that
obesity may enhance resistance to satiation (Morgan, 1974; Capaldi et al.,
1981), whereby a sated animal will continue to perform an instrumental
response to gain food reward even when the incentive value of food is low.
This concept bears many similarities to habitual responding, whereby a well-
practiced behavior can be evoked through the presence of a stimulus alone (
Dickinson et al., 1995; Killcross and Coutureau, 2003). | b********n
发帖数: 38600 | 3 but eating junk food is a matter of individual choice—and liberty. War,
famine, and genocide not so much. | k*******g
发帖数: 7321 | 4 没有junk food医院要关门，医生会失业，药厂也会关门，律师生意也会下降，政客不
吃junk food就没法扯淡。
360行都依靠junk food | b********n
发帖数: 38600 | 5 图财害命
【在 k*******g 的大作中提到】
: 没有junk food医院要关门，医生会失业，药厂也会关门，律师生意也会下降，政客不
: 吃junk food就没法扯淡。
: 360行都依靠junk food
| a*****y
发帖数: 33185 | |
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