  In a recent work (Chattopadhyay, A. K. et al, Europhys. Lett. {\bf 91},
58003, 2010) based on food consumption statistics, we showed how a stochastic
agent based model could represent the time variation of the income distribution
statistics in a developing economy, thereby defining an alternative
\enquote{poverty index} (PI) that largely agreed with poverty gap index data.
This PI used two variables, the probability density function of the income
statistics and a consumption deprivation (CD) function, representing the
shortfall in the minimum consumption needed for survival. Since the time
dependence of the CD function was introduced there through data extrapolation
only and not through an endogenous time dependent series, this model left
unexplained how the minimum consumption needed for survival varies with time.
The present article overcomes these limitations and arrives at a new unified
theoretical structure through time varying consumption and income distributions
where trade is only allowed when the income exceeds consumption deprivation
(CD). Our results reveal that such CD-dynamics reduces the threshold level of
consumption of basic necessities, suggesting a possible dietary transition in
terms of lower saturation level of food-grain consumption. The new poverty
index conforms to recently observed trends more closely than conventional
measures of poverty and allows probabilistic prediction of PI for future times.
