http://www.nutritionandmetabolism.com/content/3/1/42

Background

The will to eat is a decision associated with conditioned responses and with
unconditioned body sensations that reflect changes in metabolic biomarkers.
Here, we investigate whether this decision can be delayed until blood
glucose is allowed to fall to low levels, when presumably feeding behavior
is mostly unconditioned. Following such an eating pattern might avoid some
of the metabolic risk factors that are associated with high glycemia.

Results

In this 7-week study, patients were trained to estimate their blood glucose
at meal times by associating feelings of hunger with glycemic levels
determined by standard blood glucose monitors and to eat only when glycemia
was < 85 mg/dL. At the end of the 7-week training period, estimated and
measured glycemic values were found to be linearly correlated in the trained
group (r = 0.82; p = 0.0001) but not in the control (untrained) group (r =
0.10; p = 0.40). Fewer subjects in the trained group were hungry than those
in the control group (p = 0.001). The 18 hungry subjects of the trained
group had significantly lower glucose levels (80.1 +/- 6.3 mg/dL) than the
42 hungry control subjects (89.2 +/- 10.2 mg/dL; p = 0.01). Moreover, the
trained hungry subjects estimated their glycemia (78.1 +/- 6.7 mg/dL;
estimation error: 3.2 +/- 2.4% of the measured glycemia) more accurately
than the control hungry subjects (75.9 +/- 9.8 mg/dL; estimation error: 16.7
+/- 11.0%; p = 0.0001). Also the estimation error of the entire trained
group (4.7 +/- 3.6%) was significantly lower than that of the control group
(17.1 +/- 11.5%; p = 0.0001). A value of glycemia at initial feelings of
hunger was provisionally identified as 87 mg/dL. Below this level,
estimation showed lower error in both trained (p = 0.04) and control
subjects (p = 0.001).

Conclusion

Subjects could be trained to accurately estimate their blood glucose and to
recognize their sensations of initial hunger at low glucose concentrations.
These results suggest that it is possible to make a behavioral distinction
between unconditioned and conditioned hunger, and to achieve a cognitive
will to eat by training.