Many of the benefits associated with fasting can be achieved with caloric restriction. One obvious benefit is fat loss, since fasting is the most extreme form of a calorie deficit.
The one downside of fasting with regard to weight loss or fat loss is the potential for elevated levels of muscle breakdown. An easy way to achieve a large calorie deficit while maintaining muscle mass is to implement a protein sparing modified fast style of dieting.
Protein sparing modified fast (PSMF) is a low calorie, short term diet, with the majority of calories coming from protein. There is no official rule on the amount of calories, but most PSMF diet plans are 800 total calories or less per day.
Most people look at dieting as a day-to-day practice, but the better strategy may be to look at things week-to-week. If, over the course of an entire week, you are in a calorie deficit, you would theoretically lose weight.
Therefore, you could conceivably eat at maintenance then implement a protein sparing modified fast once per week and still lose fat. You may even be able to eat in a slight surplus on the other days if planned correctly.
On the flipside, you could eat at a slight deficit all week then really push the deficit further with one protein sparing modified fasting day. This would accelerate fat loss even more than staying at the slight deficit. Again, the protein will mitigate muscle loss.
Another benefit of a protein sparing modified fast is that it is not as intense as a regular fast. You can still eat, and if you choose the right foods you can eat quite a bit.
Protein will make up about 70% of the calories on a protein sparing modified fast diet plan. Fats are an essential nutrient and will make up 25%. While this is below the normal recommended fat intake, consuming the right fats can make the diet as healthy as possible. Carbs will make up the final 5%, and will only come from residual sources.
Assuming an 800 calorie diet, the daily macronutrient ratios would be: 140 grams of protein, 22 grams of fat, and 10 grams of carbs.
It’s important to remember that this is a short term, aggressive diet. This means there won’t be an optimal range of nutrients being consumed. While it’s important to choose the right foods for a variety of reasons, the diet won’t be perfect.
Protein Sparing Modified Fast Meal Ideas
Food options are limited on a PSMF. The goal should be satiety rather than diversity, but it doesn’t mean the diet is limited to protein shakes and liquid calories.
Since carbohydrates are so low, there will be no direct sources of carbs. This takes foods like potatoes, rice, fruit, and grains out of the equation. The carbs will come from vegetables and trace amounts found in some protein shakes.
The basis of the diet is obviously protein. Due to the low availability of fats in the diet as well, most of the protein will come from lean sources.
Protein Shakes
The most conspicuous food choice on a PSMF is a protein shake. Protein shakes are a staple even on a balanced high protein diet, as it can be difficult to get enough protein with food alone. On a diet like this where little carbs and fats are afforded, a whey protein isolate is a great option.
Brands like Isopure and Dymatize Iso-100 are virtually 100% protein. Isopure RTDs contains zero fats and zero carbs. Iso-100 and Isopure powders vary by flavor but still fall in the 1-2 gram range.
Other forms of protein like whey concentrate, casein, and vegan sources are good options as well, but typically contain more trace fats and carbs.
Egg White Omelette
Egg whites are a quality source of protein and contain no fats or carbohydrates. Adding low calorie vegetables like spinach, zucchini, and peppers in the form of an omelette can add volume to the meal and curb hunger.
Since whole eggs are a great source of healthy fats, it would be a good idea to add one or two to the egg white omelette, as long as you can ensure you stay within the parameters of the diet macros.
Grilled Chicken Salad
Chicken is a staple in any high protein diet. It’s lean, relatively inexpensive, and easy to cook. Salads are easy to control calories, since romaine lettuce and cucumbers are virtually calorie-free.
Cabot makes a 75% fat free cheddar cheese block, which is a great addition to any salad. One serving only contains 2.5 grams of fat.
Walden Farms is a company that specializes in making zero calorie condiments and sauces. Honestly, the products can be hit or miss in terms of taste. But the ones that are good, are really good (considering they have no calories).
The best salad dressing flavors Walden Farms offers are super fruits and honey balsamic.
London Broil with Vegetables
Steaks vary massively in fat content, with London broil being the leanest. If cooked and seasoned properly it can be quite appetizing.
You can get away with most vegetables on a protein sparing modified fast, especially cruciferous vegetables like broccoli, cauliflower, and Brussels sprouts. The only vegetables high in carbohydrates that should be avoided are corn, carrots, and beets.
Cod, Tilapia, and Flounder
With the exception of halibut, many forms of white fish contain low levels of fat. Fish is a great source of protein and one of the easiest proteins to digest for most people. It’s easy to prepare on the stove or in the oven and is an easy substitute if you’re bored of chicken.
Cold Cut Turkey
While you can’t put turkey on bread in a PSMF, you can turn it into a lettuce wrap or just eat it plain. G Hughes, another company that makes low calorie condiments, has a honey mustard sauce that only has 1.5 grams of fat and 1 gram of carbs per serving which would go great with turkey.
How Long to do a Protein Sparing Modified Fast
The duration of a protein sparing modified fast is correlated with how lean an individual is to begin the diet.
Obese individuals with body fat percentages in the 30% range or higher can follow a protein sparing modified fast for upwards of 2-3 months before taking a break. The reason they are able to follow the diet for this long period is because of the energy resources, in the form of body fat, stored in the body.
In fact, an obese man once fasted (under doctor supervision) for 382 days, which goes to show how much adipose tissue plays a role. With that said, it’s unreasonable and unnecessary, to go that long for almost everyone. This is just an illustration of how far fasting, or modified fasting, can go.
Leaner individuals will not be able to follow PSMF as long as obese individuals due to the potential for health issues from sustained low calorie intake. With that said, leaner individuals have less body fat to lose anyway.
The best strategy for many people is to throw in a day or two following a PSMF protocol within the landscape of a long term diet. For example, someone may be in a consistent 500 calorie deficit and have one day per week where they follow a PSMF plan.
Individual preferences and body types will determine the overall diet strategy, but the point is that a protein sparing modified fast can be a valuable tool for faster fat loss compared to typical linear dieting.