Dr Greger's 21 Tweaks summarize his book How Not To Diet (608 pages, 2019). As of April 2020, I haven't adopted these tweaks into my food system, but here they are:

AT EACH MEAL

1. Preload with Water

   "Cold water boosts your metabolism. Have two cups before each meal to also help you feel more full." — Dr Greger

2. Preload with 'Negative Calorie' Foods

   "Just changing the order in which you eat your foods can have meaningful metabolic impact. Starting each meal with an apple, light soup or salad may also later reduce your appetite for other, high-calorie-density foods." — Dr Greger

3. Incorporate Vinegar (2 tsp with each meal)

   "Flavor meals or dress a side salad with two teaspoons of vinegar, as it has been found to assist in weight loss." — Dr Greger

4. Enjoy Undistracted Meals

   "Don't eat while watching TV or playing on your phone." — Dr Greger

5. Follow the 20-Minute Rule

   "Studies have demonstrated that boosting the amount of time food is in our mouths can result in lower caloric intake, so extend meal duration to at least 20 minutes. Choose bulkier, harder, chewier foods and take smaller, well-chewed bites." — Dr Greger

EVERY DAY: TAKE YOUR DAILY DOSES

1. Black Cumin

   "Trials have found that a quarter teaspoon of black cumin powder every day also appears to reduce body mass index." — Dr Greger

2. Garlic Powder

   "Studies have found that a daily quarter teaspoon of garlic powder can reduce body fat." — Dr Greger

3. Ground Ginger and Cayenne Pepper

   "Trials have found that ¼ teaspoon to 1½ teaspoons a day of ground ginger decreased body weight. It can be as easy as stirring the ground spice into a cup of hot water. Alternatively, adding a half teaspoon of red pepper powder into your daily diet can also help burn fat." — Dr Greger

4. Nutritional Yeast

   "Two teaspoons of brewer's, baker's and nutritional yeasts contains a type of fibre called beta-glucan and trials have found it can facilitate weight loss." — Dr Greger

5. Cumin (½ tsp with lunch and dinner)

   "A half teaspoon of regular cumin at lunch and dinner has been shown to help lose weight." — Dr Greger

6. Green Tea

   "Drink three cups a day between meals (waiting at least an hour after a meal so as to not interfere with iron absorption). During meals, drink water, black coffee, or hibiscus tea mixed 6:1 with lemon verbena." — Dr Greger

EVERY DAY

1. Stay Hydrated

   "Have nine cups of unsweetened beverages a day for women — which would be taken care of by the green tea and water preloading recommendations — or 13 cups a day for men. (If you have heart or kidney issues, don't increase fluid intake without first talking with your doctor.) Avoid diet fizzy drinks — they may be calorie-free, but their artificial sweeteners are associated with increased weight gain and abdominal fat over time." — Dr Greger

2. De-flour your Diet

   "Whole grains are better than refined grains when're trying to lose weight. But eating intact whole grains — such as muesli, brown rice and solid beans — rather than those that have been powdered, is also beneficial in feeding our good gut bacteria with starch. Instead of buying boxed breakfast cereals, make oatmeal out of whole, intact oats." — Dr Greger

3. Front-load your Calories

   "There are metabolic benefits to distributing more calories to earlier in the day, so make breakfast (ideally) or lunch your largest meal of the day." — Dr Greger

4. Time-restrict your Eating

   "Confine eating to a consistent daily window of under 12 hours in length." — Dr Greger

5. Optimise Exercise Timing

   "Ninety minutes of moderately intense activity a day is also the optimum exercise duration for weight loss. Anytime is good, but there may be an advantage to exercising at least six hours after your last meal, so typically before breakfast, before a late lunch, or before dinner if you've had an early lunch." — Dr Greger

6. Complete your Implementation Intentions

   "Change your existing bad habits to good ones, or establish new good habits, using implementation intentions. Instead of vague self-promises to "do our best," these are specific if-then plans. For example: "If I get hungry after dinner, I will eat an apple."" — Dr Greger

7. Weigh yourself Twice a Day

   "Regular self-weighing is considered crucial for long-term weight control." — Dr Greger

EVERY NIGHT

1. Fast after 7pm

   "Because of our circadian rhythms, food eaten at night is more fattening than the exact same food eaten earlier in the day." — Dr Greger

2. Get Sufficient Sleep

   "" — Dr Greger

3. Experiment with Mild Trendelenburg

   "Try spending at least four hours a night lying with your body tilted head-down six degrees, towards the Trendelenburg position by elevating the posts at the foot of your bed by eight inches, as this pulls more blood into the heart and encourages it to release a fat-burning hormone. Ask a GP first about trying this — do not attempt it if you have any heart or lung issues, acid reflux, or problems with your brain or eyes. And be careful when you get out of bed as it can make you feel light-headed." — Dr Greger