The perception that thin people are healthy people could not be further from the truth; though in contrast fat people are really mostly unhealthy people are quite true. Therefore in order to be healthy and stay healthy one should really concentrate on the nutritional value of the foods being consumed rather than the amounts. Better your health here.
Ideally small amount of food intake is best but only if these amounts consists of nutritionally balanced and healthy elements.
Exploring the various nutritional basics of each category within the food groups helps the individual to make informed choices regarding the food consumed. Upon gaining this understanding the next step would be to make the changes needed but doing so gradually would better reap positive results as opposed to drastically making the change which the body may accept for a short period of time and then reject in the long run.
Finding the foods in simpler and more variety and freshness though still maintaining some of the favorite ingredients helps the body accept the new food intake with less of a shock to the system both body and mind.
Making these changes over a period of time is also necessary if the effort is to remain continuous. Substituting certain unhealthy ingredients with healthier one while still maintain the general recipe is also recommended.
Totally avoiding unhealthy foods is of course ideal but really quite an unrealistic pressure as it causes the individual to feel deprived and stressed, therefore a better alternative would be to wean themselves slowly off the item instead.
Learning to eat in smaller portions also helps the individual start the journey towards healthy eating. For some cutting out certain foods may be such a difficult effort that the next best solution would be to try and cut down the portions. Also developing the habit of avoiding heavier meals towards the end of a day is also wise.