If someone was to ask you to explain, in a nutshell, what the Christian walk is all about, I should think you would allude to some, if not all, all of the following principles:-

The Christian walk involves:
• Walking by faith not sight  (2 Cor:5:7)  We walk by faith and not by sight.

• Not living under the law but by grace (Rom:6:14) For you are not under law but under grace 

• Not striving but resting (Heb. 4:9-10   There remains therefore a rest for the people of God, for he who has entered His rest has ceased from his own works) 
 
• Enjoying freedom within the context of responsibility   (1 Cor 6:12 and 1 Cor.10:23. All things are possible:  allowable, legitimate, lawful, you are free to do anything you please; but not all things are helpful, good for me to do, expedient, profitable,  wholesome, when considered with other things  (Amplified version)

Now I want you to simply take these four principles, which I am sure you are appropriating to some degree at least in your personal Christian walk, and simply apply them to the whole area of eating and your relationship with food.

• Walking by faith not sight.  This means that there is no need for weighing, counting calories, food portions etc because your body, indwelt by the Holy Spirit, will tell you everything you need to know about portion control.  You learn to eat when you are hungry to satisfy physiological hunger and to stop when your body signals that you are satisfied. 

• Not living under the law but by grace. There is no longer any need for dietary rules and regulations, which invariably lead to failure and guilt, but we are empowered to do the will of God by the exceeding greatness of His power which mightily works within us as we yield to Him.

• Not striving but resting. Think of all the effort you have made over the years to shed the pounds, by denying yourself all the foods you love, going hungry and trying to maintain an exercise regime way beyond anything you could hope to keep up in the long term. You thought that all you needed was more self-control so you gritted your teeth and endeavoured to try harder.  It didn’t work; you ended up defeated and demoralised – and you probably ate to feel better! But a spirit-controlled appetite involves control of the self, not by the self and as we learn to walk in the Spirit we do not fulfil the lusts of the flesh.
 
• Freedom with responsibility.  God has given us all things richly to enjoy; there are absolutely no prohibited foods.  However, we do not misuse our freedom by giving in to all the desires of our fleshly nature.  No, we recognise that since our bodies are the temple of the Holy Spirit and belong to God, that we have a responsibility to keep it in good working order.  This being the case, we choose not to feed ourselves junk.  We care about good nutrition and exercise.

Biblical weight regulation isn’t rocket science.  Really it is just sanctified common sense!  When we align ourselves with God and His Word; when we trust in Him, not relying upon human wisdom or natural strength, then all the power in Heaven is available to use to enable us to succeed so that we can truly be Fit For Life Forever!