Based on what? I eat 2000 to 3000 calories a day, almost all fat, and have done so for years. My health has never been better. Labs are great, energy is high, appetite is strong, slowly adding muscle, too! This way of eating was right for me. Maybe not for everyone, but it's been a cure-all for me. I've lost 45 pounds overall, and can see my abs as a bonus. If it hasn't worked for some, perhaps genetics or methodology are to blame. I am TRULY CONVINCED that the biggest danger to this way of eating is too much satiety. I ALWAYS eat well beyond full. Easy to do, since I only eat one meal a day most days. One awesome, joyful, fat-filled nutrition extravaganza. And some safe starchy carbs, too, or fruit in moderation! They're not the devil.
If you're looking to kill your husband's metabolism, then you've come to the right place
Huntington's is a unique ailment. I don't know what it would mean metabolically. But I'd blindly think he shouldn't eat if he's not hungry. Instead, wait for hunger to come and then eat as much as he can. But I don't know Huntington's, so filter me.
Steak, eggs, potatoes - fruits, nuts, berries and forage. Coconut milk and potent herbs and spices. Tea instead of coffee now and teeny amounts of kelp daily. Let's see how this does! Not really had dairy much, and gut seems better for it.