The resulting report examines the consequences of calorie reduction on appetite and
on resultant psychological and metabolic changes.
The University of Liverpool
review highlights eight key dieting limitations:
Avoiding starvation was a key evolutionary factor for early
Homo sapiens. A review
of key scientific literature indicates that as we reduce our calorie intake our body and
brain fight back in an attempt to sustain good nutrition. In the past this enabled
storage for times of shortage but today we are unfortunately not programmed to lose
weight when food is freely and permanently available, especially when we are
sedentary with no need to expend energy in obtaining food.
2. AS WE LOSE WEIGHT OUR APPETITE INCREASES
Both human and animal studies support the anecdotal evidence from dieters and
clinicians that calorie restriction results in a compensatory increase in appetite as the
body fights to reverse the process.
3. AS WE DIET OUR BODY USES FEWER CALORIES IN SUSTAINING ITSELF
Physiological studies show that in an attempt to compensate for reduced calorie
intake our basal metabolic rate decreases so that the body actually uses less
calories to sustain itself.
4. INCREASED PREOCCUPATION WITH FOOD
Published research indicates that dieters have a greater pre-occupation with food,
stronger urges to eat more frequently and a greater feeling of being out of control
with their eating.
5. IMPAIRED COGNITIVE FUNCTION AMD DEPRESSION
Psychological studies indicate that dieters have impaired cognitive function and
slower reaction time compared to non-dieters. Increased depression has also been
observed in dieters.
7. POOR RESTRAINT
Research also demonstrates that dieters find it hard to control their appetite after
exposure to appealing energy dense foods. This can lead to abandonment of dietary
resolve and provoke over-consumption.
8. METABOLIC CHANGES
Endocrinological studies indicate that dieting reduces the secretion of hormones that
help to control food intake. Falling levels of hormones such as leptin may contribute
to diet failure.
The authors conclude that for dieters, increases in hunger and decreases in
metabolic rate cause real barriers to success. They make a case for nutritional
strategies that both:
- prevent overfeeding by enhancing within-meal satiation and post meal satiety
- stimulate metabolic rate to compensate for reduction induced by lower caloric
Zotrim, an all-natural food supplement is a mixture of plant extracts that already has
good evidence for inducing weight loss in a placebo-controlled study. It is thought to
act both by reducing appetite and by the metabolic effects of the plant extracts.