RAW Take a carrot, and hold it to a bare flame. There is not much happens, except some charring and bad smell.

Some liquid fat (oil) in a dish and a loan to a wick. Press play on the wick saturated, and record heat and light, as the results. This is one of the best known of the source of light for humanity.

Take the set of fat, meat trimmings or tallow, or left over fat globules of meat. A game can be sufficient to flame, or a little more heat may be necessary.

Take a little sugar and treat them as the solid fat. Preheating may be necessary, or start chemical detonators, or acid, but you can with a bad smell carbon sponge.

Blend sugar with potassium nitrate (saltpeter “, a source of oxygen) and sulfur in the right proportions and you can form a small powder.

Alcohol, at least some 50% of the concentration (or “100-proof”) in a flat disc, with or without a wick. A match is light enough to flame.

All these examples, unless the core, high energy food. More than you need and your weight will increase. Limit, and you can lose weight.