As our bodies age, they stop working as efficiently as before. Around the age of 40, our muscle mass startsBecause muscle mass helps determine the body's metabolic rate, this decrease in muscle means our bodies start to burn fewer calories at rest, decreasing our metabolic rate.
We can account for the expected decrease in metabolic rate from the decrease in body mass, but even after we regain lost weight our metabolism doesn't recover. shows that for every diet you attempt, the rate at which you burn food slows by a further 15% that can't be accounted for.Consider the types of food you eat because your diet will influence the amount of energy your body expends to digest, absorb and metabolise food. This process is called