We understand your struggle and frustration with weight loss, but we want to encourage you to keep your focus on the Lord and His strength, rather than relying on your own efforts. It's important to remember that our bodies are temples of the Holy Spirit, and we should take care of them for God's glory.
Firstly, we would like to address that you did not use the name of Jesus Christ in your request. It is only by His name that we have access to God the Father. There is no other name under heaven given among men by which we must be saved. And whatever you do in word or deed, do all in the name of the Lord Jesus, giving thanks to God the Father through him. Make sure to pray to Jesus Christ, as He is the mediator between God and man.
Let's pray together:
Dear Lord Jesus, we come before You, lifting up our sister who is struggling with her weight loss journey. We ask that You grant her Your supernatural strength and wisdom to take care of her body, Your temple. Help her to make the appropriate changes in her diet and lifestyle to promote health and wellness.
Now let us discuss weight loss from the biblical perspective.
Father, help her to refocus on You, knowing that her worth is not defined by her weight or appearance, but by the fact that she is Your beloved child, fearfully and wonderfully made.
In 1 Corinthians 6:19-20 WEB, it is written:
"Or don't you know that your body is a temple of the Holy Spirit who is in you, whom you have from God? You are not your own, for you were bought with a price. Therefore glorify God in your body and in your spirit, which are God's."
And in 1 Corinthians 10:31 WEB, it is written:
"Whether therefore you eat, or drink, or whatever you do, do all to the glory of God."
Lord, give her the motivation to take care of her body for Your glory, and not for vanity or to meet the world's standards.
Remember sister, that true beauty comes from within, as told to us from Peter:
"Let your beauty be not just the outward adorning of braiding the hair, and of wearing jewels of gold, or of putting on fine clothing; but in the hidden person of the heart, in the incorruptible adornment of a gentle and quiet spirit, which is in the sight of God very precious." 1 Peter 3:3-4 WEB
Even though it is frustrating to work hard and not see the desired results, keep trying, and refocus your efforts. Make sure you are eating healthy and exercising. Remember the words of Paul:
"Don't you know that those who run in a race all run, but one receives the prize? Run like that, that you may win. Every man who strives in the games exercises self-control in all things. Now they do it to receive a corruptible crown, but we an incorruptible. I therefore run like that, as not uncertainly. I fight like that, as not beating the air, but I beat my body and bring it into submission, lest by any means, after I have preached to others, I myself should be rejected." 1 Corinthians 9:24-27 WEB
Also, remember that sleep is important to your overall health and weight loss. Make sure to get enough sleep to feel rested. God wants us to rest. In Psalm 127:2 WEB, it is written:
"It is vain for you to rise up early, to stay up late, eating the bread of toil; for he gives sleep to his loved ones."
And as always in Mark 11:24 WEB, it is written:
"Therefore I tell you, all things whatever you pray and ask for, believe that you receive them, and you shall have them."
May God give her peace and encouragement as she continues on this journey. Help her to set realistic goals and to be patient with herself as she works towards them. Help her to remember that her value is not based on her appearance or her weight loss progress, but on the fact that she is Your precious child. In Jesus' name we pray. Amen.
Stay strong and keep your focus on the Lord. He will give you the strength and wisdom to take care of your body for His glory.
Prayer Focus: God, Thank You. Thank You for loving me. God, I ask You in Jesus’ name bless me with everything that I stand in need of and everything You want me to have. Bless me to know You in truth, fall in love with You with all my heart, mind, soul, body, and strength and never fall out of love with You. Bless me to have an ever growing closer stronger, more intimate relationship with You. Bless me with the love, desire, strength, and the spirit of obedience to always delight myself in You, seek first Your kingdom, and Your righteousness. Help and strengthen me God to always respect and obey You. Bless me to trust You with all my heart, acknowledge You in all my ways, and lean not to my own understanding. 
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