"Another cause of ill-health and of inefficiency in labor, is indigestion. It is impossible for the brain to do its best work when the digestive powers are abused. Many eat hurriedly of various kinds of food, which set up a war in the stomach, and thus confuse the brain. The use of unhealthful food, and overeating of even that which is wholesome, should alike be avoided. GW 241.1"
"What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own? For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God’s."
The EGW passage directly relates to the principle of glorifying God in your body by taking care of it, as stated in 1 Corinthians 6:19-20. The EGW passage expands on how neglecting one's health through poor eating habits contradicts this principle.
"Many eat at all hours, regardless of the laws of health. Then gloom covers the mind. How can men be honored with divine enlightenment, when they are so reckless in their habits, so inattentive to the light which God has given in regard to these things? GW 241.2"
"Be not among winebibbers; among riotous eaters of flesh: For the drunkard and the glutton shall come to poverty: and drowsiness shall clothe a man with rags."
Both passages address the negative consequences of overeating and unhealthy habits. Proverbs 23:20-21 warns against gluttony leading to poverty, while the EGW passage connects unhealthy eating habits to mental gloom and a lack of divine enlightenment. The theme of negative consequences from poor eating habits is present in both.
"Brethren, is it not time for you to be converted on these points of selfish indulgence? “Know ye not that they which run in a race run all, but one receiveth the prize? So run, that ye may obtain. And every man that striveth for the mastery is temperate in all things. Now they do it to obtain corruptible crown; but we an incorruptible. I therefore so run, not as uncertainly; so fight I, not as one that beateth the air: but I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway. [ 1 Corinthians 9:24-27 .] GW 241.3"
"Know ye not that they which run in a race run all, but one receiveth the prize? So run, that ye may obtain. And every man that striveth for the mastery is temperate in all things. Now they do it to obtain a corruptible crown; but we an incorruptible. I therefore so run, not as uncertainly; so fight I, not as one that beateth the air: But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway."
Ellen White directly references 1 Corinthians 9:24-27 in this passage.